# Tecumseh HM80 Do's and don'ts?



## Jatoxico (Jan 6, 2018)

So like the title says, as best I can figure my Craftsman Tecumseh engine #143.796132 is an HM80-155370N.

I don't know much about these engines except not to exceed 3600rpm. Anything special I should know about maintenance or any weak spot I should know about? Are they generally durable etc? Thanks fellas!


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## cranman (Jan 23, 2016)

Use 5 20 synthetic...don't over rev.....and they will last....they are durable enough. and if they fail....there is the Predator!


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## Shryp (Jan 1, 2011)

I would add keep them level. Don't run it with the front auger up in the air and the handles pushed down which some people do with really big drifts.


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## nt40lanman (Dec 31, 2012)

I try to run my Tecs a little slow. I overfill the oil by 1/2" just in case and change it often. Every time you finish running it, shut off the fuel and let it run the carb dry.


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## Oneacer (Jan 3, 2011)

My Tecumseh is almost 50 years old, and it runs great ... used to be my dads Snowblower ... just change the oil and use Stabil in the gas. Never had a bit of a problem with it. It is on a Yardman 7100.

My 2 Ariens were from previous owners. I put a Briggs on one and a Predadtor 212 on the other. I actually like the Predadtor and the Tecumseh over the Briggs, although I got the Briggs with electric start for my wife, but I just pull start it.


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## Jatoxico (Jan 6, 2018)

nt40lanman said:


> I try to run my Tecs a little slow. I overfill the oil by 1/2" just in case and change it often. Every time you finish running it, shut off the fuel and let it run the carb dry.


It got an oil change last night. Sticker says 5/20 or 5/30 depending on temp. Machine has not been used all that much and in the 10 yrs I'm in the house. I would say that at least 4 of those years I never fueled it up for the season. The times I did if I only had 5-10 hrs on it the oil stayed. Little worried about acid etching but figured new oils are better at buffering.

Have no idea how old owner treated it although he seemed like a guy who did his maintenance.

With new driveway and impeller mod I want to try to use it more often. Like for those 3-5" snows that I always grabbed my Toro for. Toro is awesome but the 20" cut and lack of real self propel are drawbacks for my largish parking area and moderately sloped drive.

Thinking I'd like to rebuild the carb since the high speed jet acts a little funny. Sometimes it will bog after half way through clearing snow. Give the jet a turn and it snaps back to life. Maybe should just buy new since they're cheap enough.

I like that the carb has a float bowl drain. Running a carb dry simply by running the engine, even with choking and priming as it runs down still leaves some fuel in the bowl so that's something I think all carbs should have nowadays.


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## Mike C. (Jan 28, 2016)

If the fuel lines are dried and cracked change them now before you get a fuel leak behind the starter shroud where you can't see it-primer hose,too.

Check all the screws on the carb heat shroud fairly frequently if using the machine regularly-they like to fall out.


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## Jatoxico (Jan 6, 2018)

Mike C. said:


> If the fuel lines are dried and cracked change them now before you get a fuel leak behind the starter shroud where you can't see it-primer hose,too.
> 
> Check all the screws on the carb heat shroud fairly frequently if using the machine regularly-they like to fall out.


The machine did lose one shroud bolt sometime in the past. Had the heat shroud off last night and the primer line seems flexible as does the bulb itself. I did not check the fuel line but I ordered a new carb last night and will see what's going on when I change it.

The current carb is just a little balky. The main jet mixture screw is slow to respond to changes especially as you turn it out (rich). Nothing will happen then a minute later it will stumble until you lean it out then it can go the other way.

Also I have throttle up a little slow or it can stall and it sometimes backfires. Had the float bowl off and it was clean but the o-ring for the main jet is crumbling and some of that may have found its way where it don't belong. Also the float bowl gasket is cracked but not leaking gas. I shot some carb cleaner and ran some copper wire through the jet w/o much change.

Next step would be to pull the carb and fully clean and rebuild but that seems to be hit and miss according to what I've read and it's cheap to just buy a new carb.


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## vinnycom (Nov 6, 2017)

for the old tecumsehs, check oil b4 starting, change oil yearly because its a good thing todo. theyre almost bullet proof


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## Mike C. (Jan 28, 2016)

Jatoxico said:


> ......
> 
> Next step would be to pull the carb and fully clean and rebuild but that seems to be hit and miss according to what I've read and it's cheap to just buy a new carb.


Everyone's free to do as they please,but I'll never understand this new trend of just tossing an original Tecumseh carb and replacing with a Chinese unit.A careful cleaning will often restore them to perfect working order,usually with no parts needing replacement.Plenty of step-by-step guides out there on carb cleaning,that would be my plan.JMHO.


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## RedOctobyr (Mar 2, 2014)

If you have time & willingness to clean it and get it right, that seems good. But if you just need it working, now, I can absolutely understand simply replacing it. Especially if you have limited time available, and don't want to clean & reassemble when you finally have a chance, only to find it's still bad. Maybe you have kids, and can't get to it for a week anyhow, so in the meantime a replacement could have arrived. 

And you can certainly swap it, and then also thoroughly clean the original one later, "offline", keeping the machine functional in the meantime. 

I'm just glad that there are at least more options available to people. And I am pleasantly surprised to see that some eBay carbs have adjustable jets, which the original Tecumseh carb may not. I recently discovered that I can apparently get an adjustable eBay carb for mine, if I chose, which would be an upgrade in that respect from the OEM carb.


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## deezlfan (Nov 8, 2017)

To paraphrase a popular political phrase: *It's the oil level, Stupid!* There isn't a quicker way to ruin one than letting them get low on oil. 

My procedure for keeping any Tecumseh alive survive:

Before the season starts, I always: 

Check and or change the oil. Synthetics make it easier to pull start if needed, but it is most important to keep it full. Topping it off with a bit of dino oil is way better than risking running it at the minimum line. 

Drain the float bowl [my engine is so equipped] and access whether my fuel system needs service. Hoses, filters, clamps, cap, tank and O-rings.

Make sure my cooling fan can do it's job. Mud dauber and rodent nests must be removed and their occupants evicted. 

Wipe the motor off so I can see any fresh leaks. 

Don't lay the motor down on the recoil side when I split the tractor. This let's oil run into places it doesn't belong. 

Fresh fuel. Don't care if it had stabilizer or not because old stabilized fuel is still old fuel. The stabilizers will make your engine run crappy. I siphon it clean and burn the old stuff in the lawnmower while cleaning up the autumn leaves. Fresh fuel for pre-season test is best. 

Check the condition of the spark plug, cap and wire. Also give the kill circuit a once over. 

Having done that and gone over the rest of the blower, I start it and run it through it's paces. I rarely adjust the carb until the cold weather arrives.


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## Jatoxico (Jan 6, 2018)

Mike C. said:


> Everyone's free to do as they please,but I'll never understand this new trend of just tossing an original Tecumseh carb and replacing with a Chinese unit.A careful cleaning will often restore them to perfect working order,usually with no parts needing replacement.Plenty of step-by-step guides out there on carb cleaning,that would be my plan.JMHO.


Not going to toss it but for <$15 shipped I can pop it on and diagnose if I actually have a carb problem. Once it's on the bench I can take a good look and clean it well. Nice to have a spare.


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## vinnycom (Nov 6, 2017)

u can use cheap china carbs for their parts to keep original carbs going


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## tadawson (Jan 3, 2018)

RedOctobyr said:


> If you have time & willingness to clean it and get it right, that seems good. But if you just need it working, now, I can absolutely understand simply replacing it. Especially if you have limited time available, and don't want to clean & reassemble when you finally have a chance, only to find it's still bad. Maybe you have kids, and can't get to it for a week anyhow, so in the meantime a replacement could have arrived.
> 
> And you can certainly swap it, and then also thoroughly clean the original one later, "offline", keeping the machine functional in the meantime.
> 
> I'm just glad that there are at least more options available to people. And I am pleasantly surprised to see that some eBay carbs have adjustable jets, which the original Tecumseh carb may not. I recently discovered that I can apparently get an adjustable eBay carb for mine, if I chose, which would be an upgrade in that respect from the OEM carb.


"If you just need it working now, replace . . ."

Seriously?

"Now" does not mean wait a week(s) for the craptastic Chinese part to show, and then the time needed to rig the throttle etc. to it . . .

"Now" means spend the 30 minutes or so to clean the old one. Carbs are not magic, and the older Tecumseh carbs have about 4 moving parts (throttle, choke, float, float needle), one mechanical adjustment (float level), and there is absolutely zero magic involved. Not that someone could not screw up a rebuild (I have known folks that could screw up a sunny day . . . ) but it is one of the simplest tasks I have done in a long time. From the sound of your gaskets, a carb kit would be a good idea, and I always find those in stock locally . . . IE "Now". And unless you short-cut something and don't to a full rebuild/clean, the chance of a problem persisting is minimal. Remember, 4 moving parts! Unless the rest is mangled/deformed/etc. there really isn't much to fail.

Just did this on a 1979 HSK70 that sat likely 20 years with god knows what fuel in it. Shutoff closed, but bowl full . . . . Most godawful green goo I have ever seen in it. Rebuild and new fuel lines (upper was solid with rubber residue - zero flow, as was shutoff valve. New lines and cleaned shutoff, and other than one other issue (that would have been easy to blame on the carb, but wasn't) of the small intermediate manifold between the carb and the block being loose from the block, causing an air leak, it now runs flawlessly and starts on 1 pull in 12 degrees . . . . and back in service likely before the right clone carb could have been found and ordered.

Just another point of view. Good, older, equipment like this was built to be serviced. It's only recent attitudes that have pushed folks into treating everything as disposable . . .


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## Jeepetti (Jan 23, 2018)

Unless there is something catastrophically wrong with the original carb, I rather take the time to clean it than replace it.


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## cranman (Jan 23, 2016)

I don't bother cleaning anymore...unless it a carb that I can't get from China. I keep 1/2 dozen of the small and medium block Tec carbs on hand at all times...some adjustable, some not. I haven't gotten a bad one yet.


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## Jackmels (Feb 18, 2013)

Mike C. said:


> Everyone's free to do as they please,but I'll never understand this new trend of just tossing an original Tecumseh carb and replacing with a Chinese unit.A careful cleaning will often restore them to perfect working order,usually with no parts needing replacement.Plenty of step-by-step guides out there on carb cleaning,that would be my plan.JMHO.


Depends What Your Time is Worth. I'd rather spend $12 and fix the problem, especially if your engine has a Fixed Jet Carb. Replacing it with an Adjustable Carb Allows You to Dial it in.


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## Dauntae (Nov 10, 2016)

Yes time is money in many cases, I usually have a few jobs to do and have to be in bed early so a lot of times a $12 carb is much easier and worth it, I also take the old carbs and clean and fix them to use if needed on the next job. So many times they get used but when someone is waiting right before a storm, I will toss a new one on and deal with cleaning the old one later.


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## Jatoxico (Jan 6, 2018)

No expert by a long shot but I've cleaned and rebuilt my share of carbs. Never had another Snow King and this one has had limited use by my hands so I don't have a good baseline of performance. Problem with snowblowers is unlike your lawn mower, generator, leaf blower etc, you can't run them under a good load without snow so I'm stuck guessing.

It has operated well but have had the intermittent minor issues described above and I feel like it's a bit off. Since I'm not 100% it's a carb issue I'm using the new one to eliminate it as a variable. So as a $14 diagnostic "tool" this is the right way to go this time, for me.

Plan on going to go through the whole fuel system this weekend.


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## tadawson (Jan 3, 2018)

My experience on my Snow King is main jet reponse is virtually instantaneous when running right. Moving the needle in or out and having to come back is consistent with displacing crap in the needle. Since you already have an adjustable main jet, very little is to be gained in replacement, other than avoiding a bit of work you may or may not want to do. Rebuild kits are also about $12, so no cost savings in a replacement for a DIY either, nor will you learn more about the carb for if/when next time hits.

Check the float bowl for crap, and if found, flush lines and tank well (this would need to done even if a new carb), and if line is old, replace - it'll never get any easier. Deep clean/rebuild the carb, and that should be good as well. One other thing to check which will make the mixture seem to jump all over, is that on a lot of thE older Tecumseh engines, there is an intermediate manifold that bolts to the block, and the carb bolts to that. Mine had come loose, and the variable air leak presented very much the same as you describe, and simply grabbing the main needle to adjust it would change that as well. Verify all tight, good gaskets, etc. and should be good.


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## Mike C. (Jan 28, 2016)

Jackmels said:


> Depends What Your Time is Worth. I'd rather spend $12 and fix the problem, especially if your engine has a Fixed Jet Carb. Replacing it with an Adjustable Carb Allows You to Dial it in.


I can buy a complete rebuild kit for less than $10,clean the carb and install the kit in under an hour.99% of the time,that fixes the problem.

Like I said,to each his own.


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## Jackmels (Feb 18, 2013)

Mike C. said:


> I can buy a complete rebuild kit for less than $10,clean the carb and install the kit in under an hour.99% of the time,that fixes the problem.
> 
> Like I said,to each his own.


My Time is Worth Quite a Bit More than $10 an Hour when I'm Wrenching, But Like You Said, To Each His Own.


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## tadawson (Jan 3, 2018)

To me, working on my own gear, my time is an investment in doing it right, and a non factor. I would also not knowingly ever use any shop that subbed in Chinese parts to raise profits without full disclosure, and the option to use parts that were not crap. I do a fair amount of auto work as well, and you almost never hear about how good Chinese parts are, but rather how many very early failures, and often how many engines are destroyed. This is so bad, there is an acronym: CRAP - Chinese Replacement Auto Parts . . . . And I find it hard to fathom that small engine parts sold by the likes of fly by night internet vendors can be better. Maybe a Chinese firm with a US presence, actual address, ability to contact, and possibly support, then maybe (and yes, HF does give that for their engines, but still very little support) but for carbs, it's a pure roll of the dice, and the main reason they work at all is the same reason a rebuild is so easy - they just aren't that complicated and don't take that much time or skill!

I do think that I am unique (or a dying breed) in that I can see the value of doing a repair right the first time, even if more expensive, since if I cheap it out with bad parts, I'll likely be doing it two or three times, which is a guaranteed loss financially. Sadly, I think the younger generations were not raised with that forward vision, and it's all about disposable and cheap . . . . filling the landfills with massive amounts of wasted resources because they couldn't be bothered to repair something trivial, or the manufacturer made it impossible.


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## Jatoxico (Jan 6, 2018)

tadawson said:


> TAnd I find it hard to fathom that small engine parts sold by the likes of fly by night internet vendors can be better. Maybe a Chinese firm with a US presence, actual address, ability to contact, and possibly *support*,
> 
> *the main reason they work* at all is the same reason a rebuild is so easy - they just aren't that complicated and don't take that much time or skill!
> 
> *I can see the value of doing a repair right the first time*,


Support? For a $14 carb?

So you admit the carbs work which is what I concluded after researching these and past projects.

As far as "doing it right" by rebuilding, wanna guess where the rebuild parts are made?

Seriously, I don't know what your ranting about at this point. The old carb is not going in the trash and will be rebuilt and kept as a spare.


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## FlamingSpaghetti (Jan 8, 2018)

If you want to count the HMSK80 engines as well, I quite like these. I find them to be pretty durable and well made and as long as you don't over-rev them and throttle them down a hair when not under load, they last a long time. I have one on my MTD that I bought used from a plow company so who knows how much abuse it's received before me. I always check the oil and do seasonal oil changes before use and it's never let me down. Not the most efficient engine out there but these old L-head engines have taken the test of time and proved themselves. Not much can go wrong and they're super easy to work on.

I wonder why they have gained a reputation for throwing a connecting rod. Does anyone know the true reason these can be found with a hole in the side of the block? Is it from over-revving or is it lack of maintenance?


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## Jatoxico (Jan 6, 2018)

FlamingSpaghetti said:


> If you want to count the HMSK80 engines as well,
> 
> I wonder why they have gained a reputation for throwing a connecting rod. Does anyone know the true reason these can be found with a hole in the side of the block? Is it from over-revving or is it lack of maintenance?


Good question. I sometimes see discussions on Tecumseh motors kind of lumping them together and don't know what, or if there are any major differences between the HM and HMSK motors.


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## tadawson (Jan 3, 2018)

Jatoxico said:


> Support? For a $14 carb?
> 
> So you admit the carbs work which is what I concluded after researching these and past projects.
> 
> ...


No, I don't admit that . . . . all you guys touting this dung make is somewhat apparrent that some have gotten them to work. Others have had fit issues, control connection issues etc. And yes, support! It's a really novel concept that there might actually be an opportunity to get parts formor return a defective item . . . . 'disposable' is *NOT* the solution! And the rant is simply that we should give *ZERO* funding to China for this junk! Oh, and my rebuild parts come from American companies that (wait for it . . . ) support thier products!


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## tadawson (Jan 3, 2018)

FlamingSpaghetti said:


> If you want to count the HMSK80 engines as well, I quite like these. I find them to be pretty durable and well made and as long as you don't over-rev them and throttle them down a hair when not under load, they last a long time. I have one on my MTD that I bought used from a plow company so who knows how much abuse it's received before me. I always check the oil and do seasonal oil changes before use and it's never let me down. Not the most efficient engine out there but these old L-head engines have taken the test of time and proved themselves. Not much can go wrong and they're super easy to work on.
> 
> I wonder why they have gained a reputation for throwing a connecting rod. Does anyone know the true reason these can be found with a hole in the side of the block? Is it from over-revving or is it lack of maintenance?


I'll guess both of those, aggravated by age (which proper maintenance would nullify).


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## Jatoxico (Jan 6, 2018)

tadawson said:


> 'disposable' is *NOT* the solution! And the rant is simply that we should give *ZERO* funding to China for this junk!


You do realize this thread is about keeping a 30 y/o Tecumseh fitted Craftsman going instead of sending it to dump right? At this point you're just derailing this thread.


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## tadawson (Jan 3, 2018)

Jatoxico said:


> You do realize this thread is about keeping a 30 y/o Tecumseh fitted Craftsman going instead of sending it to dump right? At this point you're just derailing this thread.


No, I'm encouraging the owner to fix it right . . . . and have pretty much given him procedures what to do, as opposed to throwing garbage parts on it and potentially hastening it's demise . . . . And frankly, there have not been too many of us making useful suggestions along that line . . . . *and* he gets to learn far more about his engine which will help in the future. I'm not the one that keeps tooting about garbage parts . . . . but do feel it necessary to defend the attacks and clear the myths . . .

I also feel I have offered the most certain path to quick success. A rebuild *will* fit, it will not be defective out of the box, etc. etc. etc., and you don't wait for it to ship from god known where for weeks . . . .


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## RedOctobyr (Mar 2, 2014)

I've had 2 HMSK80'S, both were around 20 years old. On one, I sometimes noticed a muffler glow. 

I checked the valve clearances, and found the exhaust, I think, was under-spec on the clearance. Apparently, over time, the valve can sit a little deeper in the valve seat, giving smaller valve clearance. I had to remove the valve, grind off a few thousandths of an inch from the back, and re-install it. It seemed better after that, maybe even a bit more power. 

It could be worth checking on yours. Checking isn't difficult, though changing the clearance is a pain. But if you find the clearance is too small, the fix gets more involved if you wait until the valve or valve seat are damaged, due to not closing fully while running.


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## Jatoxico (Jan 6, 2018)

RedOctobyr said:


> I've had 2 HMSK80'S, both were around 20 years old. On one, I sometimes noticed a muffler glow.
> 
> I checked the valve clearances, and found the exhaust, I think, was under-spec on the clearance. Apparently, over time, the valve can sit a little deeper in the valve seat, giving smaller valve clearance. I had to remove the valve, grind off a few thousandths of an inch from the back, and re-install it. It seemed better after that, maybe even a bit more power.
> 
> It could be worth checking on yours. Checking isn't difficult, though changing the clearance is a pain. But if you find the clearance is too small, the fix gets more involved if you wait until the valve or valve seat are damaged, due to not closing fully while running.


Thanks RO I will keep an eye out for this. I never noticed the problem you describe but don't want to ignore anything that could cause me have to replace the engine. It's a dual shaft output so no easy Predator re-powering here.

The engine runs and if I had to use today I could, just seems to require regular readjustment on the fly as I said. Once I have the carb off and in hand something may be obvious. The current carb bowl was completely clean (I'm pretty good about running stuff dry etc before storage) and a quick going over didn't change how it responded to adjustments to the main jet.

I should have everything I want to do done this weekend (also want to make sure the rpm's are adjusted to around 3500). Once it's up and running I'll let it run for a good amount of time and check some stuff. Looking at the plug I think I had it set a little rich but right now it's so slow to respond to adjustments that it's hard to get it right.


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## Kiss4aFrog (Nov 3, 2013)

Jatoxico said:


> Good question. I sometimes see discussions on Tecumseh motors kind of lumping them together and don't know what, or if there are any major differences between the HM and HMSK motors.


One of our senior members who has restored a number of Craftsman blowers recently mentioned he pulled his out to do the drive and had it at 1/3 throttle warming up when, clunk, quit. Went to restart and no compression so he's thinking .... ROD. He didn't see a hole in the case but I mentioned to him it might be because his broke at a reduced RPM.

I think the reason we worry about it is it's something that comes up here often as a problem but out in the real world numerically there are very few failures. I tried to find a replacement strengthened or redesigned rod and nothing is available. In my automotive mind I conclude that if there was a problem with the rod someone by now would be offering a stronger one for people who use these on go carts and mini bikes since so many other parts are available. Just my two cents.


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## FlamingSpaghetti (Jan 8, 2018)

Kiss4aFrog said:


> One of our senior members who has restored a number of Craftsman blowers recently mentioned he pulled his out to do the drive and had it at 1/3 throttle warming up when, clunk, quit. Went to restart and no compression so he's thinking .... ROD. He didn't see a hole in the case but I mentioned to him it might be because his broke at a reduced RPM.
> 
> I think the reason we worry about it is it's something that comes up here often as a problem but out in the real world numerically there are very few failures. I tried to find a replacement strengthened or redesigned rod and nothing is available. In my automotive mind I conclude that if there was a problem with the rod someone by now would be offering a stronger one for people who use these on go carts and mini bikes since so many other parts are available. Just my two cents.


What about a billet rod for the HM100 engines? Isn't that the same connecting rod and crank, just a larger piston? I know they make a billet rod for that engine.

http://www.arcracing.com/6286-tecumseh-hm100-3-95-billet-rod/


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## Robert A Fierro (Jan 24, 2018)

re: "Next step would be to pull the carb and fully clean and rebuild but that seems to be hit and miss according to what I've read and it's cheap to just buy a new carb."

OK if you can get a USA built carb. If its chinese, save the old carb! 

ALSO.... if snow blower is a pre ethanol unit ( approx 2005), replace the fuel hose.


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## Kiss4aFrog (Nov 3, 2013)

Mike C. said:


> Everyone's free to do as they please,but I'll never understand this new trend of just tossing an original Tecumseh carb and replacing with a Chinese unit.A careful cleaning will often restore them to perfect working order,usually with no parts needing replacement.Plenty of step-by-step guides out there on carb cleaning,that would be my plan.JMHO.


One thing to consider is if it's original or if it's been cleaned or rebuilt and that person had a part or two left over :sad2: If that's the case you might never get it running right if you can't identify what's missing or even damaged when someone tried to get it apart or back together.


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## Mike C. (Jan 28, 2016)

Jatoxico said:


> .....The old carb is not going in the trash and will be rebuilt and kept as a spare.


That makes perfect sense,and what I would think most people would do.My earlier point was merely that I'm surprised at how many people will take off an originalTecumseh carb and heave it right in the trash without even attempting a simple cleaning that costs basically nothing.

My original intention wasn't to single you out for criticism,I was just making mention of a trend I noticed,not just on these forums,but many others.No offense intended although it may read that way.


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## Mike C. (Jan 28, 2016)

Kiss4aFrog said:


> One thing to consider is if it's original or if it's been cleaned or rebuilt and that person had a part or two left over :sad2: If that's the case you might never get it running right if you can't identify what's missing or even damaged when someone tried to get it apart or back together.


Good point.I can only speak for myself in that I've worked on enough of them that a missing part or damage would be noticed.A novice might not be so lucky.


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## Mike C. (Jan 28, 2016)

Jackmels said:


> My Time is Worth Quite a Bit More than $10 an Hour when I'm Wrenching, But Like You Said, To Each His Own.


I don't work on small engines for a living.I have a few neighbors I help occasionally and that's it.I learned to work on my own stuff because I won't pay the shop two towns away $65/hr. and then go back over and straighten out what they supposedly repaired.


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## Mike C. (Jan 28, 2016)

Jatoxico said:


> As far as "doing it right" by rebuilding, wanna guess where the rebuild parts are made?
> 
> .


Maybe there lies the secret of my success with rebuilds,I'm able to use US made,OEM rebuild kits.There's a fellow down the road from me who went out of the small engine repair business years ago that still has the Tecumseh kits.I've tried many times to buy out some of his Tecumseh parts in one lot(and he has TONS)but he won't sell.

To be honest,the Stens kits I've bought are good quality too.Whether that will continue to be true,who knows.


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## Jatoxico (Jan 6, 2018)

Mike C. said:


> That makes perfect sense,and what I would think most people would do.My earlier point was merely that I'm surprised at how many people will take off an originalTecumseh carb and heave it right in the trash without even attempting a simple cleaning that costs basically nothing.
> 
> My original intention wasn't to single you out for criticism,I was just making mention of a trend I noticed,not just on these forums,but many others.No offense intended although it may read that way.


None taken. And I agree it's amazing how wasteful some people are, tossing out perfectly good products because they don't want to repair, because the color is no longer in or because they never needed it in the first place.

From the sound of it, like you and probably many here I don't like to be wasteful that way so I do a lot my own maintenance and repairs.

Sometimes I think I'm the crazy one since it takes time and effort and maybe I should just join the herd and "consume" like a good American.


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## Mike C. (Jan 28, 2016)

Jatoxico said:


> ....
> 
> Sometimes I think I'm the crazy one since it takes time and effort and maybe I should just join the herd and "consume" like a good American.


No...never.I like learning too much and saving money too much not to repair things if possible.And let's face it,these old engines and original parts will never be made again,I want to save as many as possible.I'm not a huge Tecumseh fan,but I hate to see them disappear just the same.


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## tadawson (Jan 3, 2018)

Question to the OP: You say the main setting is not stable . . . A couple of things to check: 

How many turns out is it when you set it and it runs OK? If much more than the typical 1-1/2 or so, you might have an air leak, and the one time I found this, my needle seemed very sluggish as well, and was at closer to 3 turns to balance with the excess air. It would not idle well (if at all).

Second, have you checked the position when it goes out? If the spring or O-ring on the needle are weak of failing, vibration could cause it to move (but not explain the sluggish response).

A high float level (bad float/float valve/seat) could also allow excess fuel to flow somewhat randomly, which I think could also cause what you see.

In any case, when at full power, the idle circuit isn't doing much, so the main needle assembly and the two small orifices in it's sides are in play, as is the main jet going through the center of the carb into the venturi. If the float level is correct, and these clear, full power should be good . . . the rest mainly affect idle and transitional throttle. 

But in any case, when you pull the carb, pull any and all intake manifold part(s) present, and verify gasket integrity and snugness of hardware.


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## Jatoxico (Jan 6, 2018)

tadawson said:


> Question to the OP: You say the main setting is not stable . . . A couple of things to check:
> 
> *How many turns out is it when you set it and it runs OK? *If much more than the typical 1-1/2 or so, you might have an air leak, and the one time I found this, my needle seemed very sluggish as well, and was at closer to 3 turns to balance with the excess air. It would not idle well (if at all).
> 
> ...


It's hard to gauge how many turns out makes it happy because it seems to suddenly change and responds slow as I said. The main reason I know there's a problem is that I can turn the main jet out until it's ready to come out w/o any change (it does stumble/respond as I dial it in). Obviously that's no good so I end up leaving it a few turns out and it runs pretty ok then all of a sudden starts to stumble again.

Agree about an air leak and mentioned the cracked bowl gasket as a potential source of air. Don't know if t's bad enough to cause an air leak though. I tightened/checked the intake to the block (was tight). Definitely will be making sure all connections and gaskets are good as well as fuel lines etc.


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## tadawson (Jan 3, 2018)

The bowl is vented to the atmosphere via a small port on the carb - it's a problem if isn't . . . . and since all jets/ports are submerged, there is no air path into the engine from the bowl anyhow. The main thing a shot bowl gasket will donis keep the primer from working, since it works by gently pressurizing the bowl, driving fuel into the venturi. Oh, and containing spills as the fuel sloshes or the machine is tipped.

When you had the bowl off, did you inspect the needle seat/bowl nut to ensure no gunk in either small passage, or beteen the needle and it's seat, and that the needle has no marks/ridges/scoring/etc on it? Same with the seat . . . Crunch one in hard once, and it's pretty much junk . . .

And if the engine will run much more than 2 to 2-1/2 turns out, that is very unusual . . . most die before then due to being massively rich.

Have you checked the float level, and float seat to ensure correct fuel level in the bowl?


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## Jatoxico (Jan 6, 2018)

tadawson said:


> The bowl is vented to the atmosphere via a small port on the carb - it's a problem if isn't . . . . and since all jets/ports are submerged, there is no air path into the engine from the bowl anyhow. The main thing a shot bowl gasket will donis keep the primer from working, since it works by gently pressurizing the bowl, driving fuel into the venturi. Oh, and containing spills as the fuel sloshes or the machine is tipped.
> 
> When you had the bowl off, did you inspect the needle seat/bowl nut to ensure no gunk in either small passage, or beteen the needle and it's seat, and that the needle has no marks/ridges/scoring/etc on it? Same with the seat . . . Crunch one in hard once, and it's pretty much junk . . .
> 
> ...


That makes sense. I only wondered if it _was_ pulling additional air from above the gas in the bowl that it may not be sucking fuel through the jet efficiently. Possibly (?) that could explain the delayed response as I try to richen the mix by opening the jet.

The float level was checked in the past and seemed fine. I could not (did not) inspect the needle or seat with the carb on the machine and did not pull the float this time but the o-ring on the main jet was in poor shape so it would not surprise me to find other components in similar condition. It does not leak but is it sticky and hanging up?, I don't know yet.


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## tadawson (Jan 3, 2018)

Again, there is no possible passage in a normal carb that would allow air into the intake from the float bowl . . . that side is pure wet, and also small enough to not likely make much difference. The bigger issue would possibly be no vent, and a mild suction being pulled in the bowl, preventing flow, but that should stay pretty constant due to new fuel coming in, so no air movement, just needs to be at atmospheric. Leaks big enough to really affect running are typically the seals carb to maniford, and manifold to block. Float level was checked to be 11/64" (or a #4 drill bit) IIRC? Can't really do that with the carb in place either . . . 

The main jet O ring could cause a drip, or allow the needle to slip. It sounds like the rubber parts on this carb are in very bad shape, and you just need to take the minor amount of time to put in a kit. If the carb is clean inside, you could just do the kit without pulling the welch plugs - maybe 10 minutes to drop the bowl, blow it out with cleaner, put the float back in and set it, reinsert the needles, put the bowl back on and test. I don't know you, but I really think you are far overcomplicating the process of cleaning/rebuilding one of these carbs in your mind . . . it really is easy . . . and likely could have been done multiple times over in the amount of time that this discussion has been going on. Were we not so far apart, I'd gladly show you how to do it (although there are excellent videos out there as well).


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## Jatoxico (Jan 6, 2018)

tadawson said:


> A I don't know you, but I really think you are far overcomplicating the process of cleaning/rebuilding one of these carbs in your mind . . . it really is easy . .


Not sure what you mean, I have no fear or concern about doing a rebuild. Just after reading what others have said that did Tecumsuh's they thought it could be hit and miss with these carbs. You clearly don't agree. That's good, I hope you're right and I end up with a good spare one way or the other. I'll find out for myself this weekend once I have it on the bench.


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## tadawson (Jan 3, 2018)

Jatoxico said:


> Not sure what you mean, I have no fear or concern about doing a rebuild. Just after reading what others have said that did Tecumsuh's they thought it could be hit and miss with these carbs. You clearly don't agree. That's good, I hope you're right and I end up with a good spare one way or the other. I'll find out for myself this weekend once I have it on the bench.


And a lot of us say 99% success . . . . I take that to mean the others are doing it wrong (or just don't want to), not that the process is in any way flawed. 40 years and never had a rebuild fail to work as good as new. The only case I would not build is heavy mechanical damage to the carb irreperably altering the main casting . . . . If that's intact, good to go.

Also, based on what you describe, I see this as a 'no way to lose' prospect. Short of sledge hammer it, I defy you to make things worse, and pretty much unusable as is, so my mind sees this as a 'dive in - nothing to lose' situation.

You will still need to check the manifold seals for leaks, since they are external to the carb . . . if there is a leak there, the new one will behave the same . . .


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## Jatoxico (Jan 6, 2018)

*Update*

Replaced;

Fuel Shutoff Valve
Carburetor
Spark Plug
Gas Cap (vent on old one was broken)

Took the time to rattle can all brackets and shrouds as well as filing up and painting the scraper bar while I was at it.

Started and ran right away which I expected as it ran on the old carb. Initially it was surging at high throttle no load but not with augers engaged. After adjusting both high speed circuit and the idle screw I was able to clear that up. It runs _just a little_ "ratty" to my ear like it's slightly rich but if I back off any more on the main jet it starts to pop and stumble. Probably better slightly rich since in the cold (its 50F here today) and under a load I'm guessing it prob be happy.

It does sound pretty good with augers and in drive and I tried to hold it back to put as much load on it as I could and it stayed strong.

So anyways it got some love and looks prettier. Now to see how it works with the new impeller mod.

Oh and I'm a little embarrassed to say that I had taken the word of the previous owner and used his spark plug marked snow thrower. Turns out when the new one came it was not correct and probably the electrode did not protrude below the head. It's right now.


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## Kiss4aFrog (Nov 3, 2013)

Where are the photos ??


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## Jatoxico (Jan 6, 2018)

Not much to see all buttoned up but here ya go!


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## FlamingSpaghetti (Jan 8, 2018)

Wow! That sure is a clean machine!


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