# ST1032 underpowered?



## MX-Dad (Oct 24, 2020)

New owner of an older ST1032. Any thoughts on if the Ariens 1032 will be under powered? 32" bucket with a Tecumseh HM100 (10 hp)... looks like about 358cc from what I can tell. I've seen RPM variations upto 3750 based upon different mfgr applications, but I think Ariens is suggesting 3600. In the automotive world, usually higher RPMs yeild higher HP, but I'm not sure that's the same with the HM100 power plant. Seems odd the carb is identical between the HM80 and HM100. Hmmm? I'd love to hear your thoughts.

The rest of the blower is a BEAST!!! Nicely engineered IMO. 

I would like to retro-fit a taller shoot and remote top deflector. We will see.


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## GoBlowSnow (Sep 4, 2015)

I would not suggest higher than 3600 RPM.


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## deezlfan (Nov 8, 2017)

The 10hp Tecumseh was the go to engine for most manufacturers that made 32" & 33" wide blowers for many years. Heck, in the early 70s, Ariens made 32s with 7hp and 8hp engines and they sold a bunch of them. There really isn't any good way to hot rod a Techie flathead in an economic way and pushing them past 3600rpm is asking for trouble.

If you find that you need a 32" blower and yours is underpowered, you should at least do a proper tune up which would include adjusting valve clearances. Once you are sure it is running as strong as it was designed to, you have to decide your next step. Keep or make a change. 

If you aren't happy, either trade it for a more powerful and/or narrower machine or engine swap to a more modern design with more power. The overhead valve engines available now can be purchased in larger displacements than the H100. Downside is that once you get to the larger OHV engines, you may have to deal with larger engine block and crankshaft sizes which means different pulleys and alignment issues that you would need to work through.


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## deezlfan (Nov 8, 2017)

> In the automotive world, usually higher RPMs yeild higher HP,


Yes, but with quickly diminishing torque numbers. When you want to pull a heavy trailer up a long hill you don't use a high revving race engine. You use a high torque low revving truck engine. Horsepower doesn't do the work, torque does.


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## 140278 (Aug 27, 2020)

good points!

10 hp should have a one inch pto like most higher hp/torque rated motors, pto length will need to be checked hopefully match what's needed. what will be is crank center line to mount base height, making a need to find longer belts


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## JLawrence08648 (Jan 15, 2017)

If you don't have torque, a high rpm engine will slow down once it hits a wall. Two examples, push a low torque drill hard you can stop it, a 1/2" high torque drill will twist your arm off, or go up a hill with a car in 4th gear, you will slow down, bog down, then stop if you don't shift.

I do agree a 10hp Tecumseh engine is underpowered for a 32" swath.


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## deezlfan (Nov 8, 2017)

My 1988 Craftsman II 10/32 has plenty of power. Never been tempted to go larger. 

Just brought home a couple of 1972 Ariens with a 32" bucket and am awaiting snow to test the original 8hp Tecumseh. I have a HM100 on the shelf if I want to go larger. Question is what alternative would be above and beyond 10hp that wouldn't exceed the value of the blower after modification? The 13hp Briggs' are pricey. The 13hp Predator is much larger and would probably need a motor plate fabricated. Still in the $400-500 dollar range all in.


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## dman2 (Sep 22, 2019)

I watched snowplowing a lot and those 10/32 snowblowers didn't seem to bog down at all. It is because they scoop up large amount of snow, but don't throw it very far. Their impeller design work better at getting rid of the snow.

A modern snow blower is front heavy, throw snow at the tip of the impeller blades and throw it far. It requires more power to do that.


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## MX-Dad (Oct 24, 2020)

I did consider the torque issue. The impeller on this machine has 6 vanes and the chute opening is oblong, not round. If the machine doesn't bog down, my thought was to increase the impeller speed to throw farther (hense higher RPM)... but perhaps a bigger engine pulley might be a better answer. I have a large driveway, and need to get all the snow past the house before blowing it sideways off the drive. So the 32 inch width would be very welcome... however the extra width must come 2nd in priority to how far it can throw. I guess time will tell.


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## Kiss4aFrog (Nov 3, 2013)

Trust me, stick with the 3,600 RPM limit. More than just brute RPM you need to have the torque to keep it there especially under load.
To get better distance consider an impeller mod first. That will help to toss more snow out each rotation and give a bit more distance.




Next, slightly larger motor pulley as it will increase your impeller speed but also put more stress on gears, bearings and bushings in the impeller and auger system. So you need to weigh pros against cons. I'd ask around on what size you might consider as too big and you'll start eating up components, maybe belts too. You only need a slight increase in OD of the pulley and you have to remember you want to have torque available to chew into drifts.
Is a 10 hp 32" underpowered? There isn't a yes no answer to that. I have a 1323 Toro that just doesn't bog. I have an older (than yours) 1032 Areins that will chug a bit with heavy EOD piles. If you end up tossing snow on top of snow that then has to be tossed again I'm guessing the 10 is going to be working pretty hard or you might need to take less than a full bucket. Except for really extreme wet heavy snow or the occasional nasty EOD pile I think the 10 hp will get the job done. I would definitely recommend doing the impeller mod on it.

Deluxe 28 I bought with ventilated block. This is why you want to stick to 3,600


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## MX-Dad (Oct 24, 2020)

OK on the RPM limit, although in searching through some Tecumseh technical documents, at one point Dewalt did source that motor on some piece of equipment and the RPM spec was at 3750, so I thought maybe it would be OK. I did intend to do the impeller mod. Anybody with suggestions on up-sizing the drive pulley, and where to find or get one? I don't like to second guess the engineers who designed the blower. But 15-20% increase in impeller speed could help the throwing distance alot. I would never be opposed to taking a partial bucket to get the distance when needed. I just MUST have the throwing distance.


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## JLawrence08648 (Jan 15, 2017)

I prefer Tecumseh to be run at 3450-3600 and prefer the lower range.


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## MX-Dad (Oct 24, 2020)

JLawrence. Not that I disagree, but I would also love to know the reason for that decision.


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## Kiss4aFrog (Nov 3, 2013)

I tried to find an authoritative source to link but all I can find is discussions with 3,250 - 3,600 rpm being the number people have in their documentation (operator manuals, service info, ...) for setting the governor on the Tecumseh.

.


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## MX-Dad (Oct 24, 2020)

On page 29, This Tecumseh manual shows a medium frame HM100 spec out for 3400 up to 3750 for some Dewalt applications. However the majority (by far) has the RPM limit at 3600. I noted the bore and stroke on that page for the english measurement is mis-stated and I believe it should be 3.312" x 2.532" = 21.82 cu in. (84.13mm x 64.31mm = 348cc). Also interesting to note that many of the other models have that same displacement, along with the same RPM limit of 3600 RPM are rated at 11HP and 12HP. To me those details seem suspect. Wonder if it was just more "fake news", even back then? Does anyone out there have some experience or facts to add?
http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/engine-specs_line-drawings.pdf


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## Shovel (Mar 26, 2019)

MX-Dad said:


> JLawrence. Not that I disagree, but I would also love to know the reason for that decision.


There is much less stress on the rod at reduced RPM...rotational forces increase by four when speed is doubled.
When we yank the piston back down..force is also quadrupled when speed is doubled.
There is 27 percent less force on the rod at 3600 vs 3200 rpm.
Also our engines use 5/30 oil.
In many owners manuals for vehicles 5/30 is not allowed for substained high speed driving...3600 rpm in an automobile is high speed operation.
The oil relies heavily on the additives to make it a 5/30 oil..there are 'strands' that coil and uncoil depending on the temperature..these strands line up on the crank journal expodentially with increased engine speed...which has the oil acting closer to the 5 weight rather than the 30 weight on the crank journal.

Also the dipper(our engines vs automobile engine) has to slice through the oil.
When the dipper hits the oil to splash oil it creates a void ..the oil has to flow back to the void..the faster the engine is running there is less time for the void to become filled..with a splash engine you have less lubrication during high speed operation while you are needing it the most.
We ended up with our high speed engines due to the speed needed for generators as we need to keep at 60hz which is how 3600 and 3750 came into play.
3750..when you apply a load it ideally pulls you to down 3600 rpm.
A generator running 50 hz will be running 3000 rpm..many parts of the world run at 50 hz.
Also although many of our small engines are rated for 3600 rpm..many manufactures have them set slower than 3600 when they are installed in piece of equipment they will be in.
Also to add...if an engine is rated 3600 max..if it is set no load 3600 rpm..it will be running faster than 3600 while it is surging..when a load is released from the engine the governor will overshoot..the engine may briefly see 3900 rpm during surging and when loads are released...which is over speeding..all those over speedings add up..as a result our cheap rod snaps. 



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## MX-Dad (Oct 24, 2020)

Thank you for the detailed reply. I cannot disagree and certainly don't want to rethink the Tecumseh engineering that has proven these engines over the years. I think I need to disagree with the comparison to an automobile or motorcycle engine lubrication system though. IMO they are not really similar. Auto systems use a positive displacement pump to lubricate. If the proper oil is used in a good condition engine, the rod and crank should never even touch each other when running. During operation there is a thin film of oil that isolates the parts. My Lexus runs over 3500 RPM at highway speeds out west for hours at a time, that combined with my very common redline acceleration habits up to 7000 RPM (with over 210,000 miles at this point) should make a good case. The dip solution that Tecumseh employs has proven to work, but I agree with you that there must be limitations, and your declarations make sense in my mind. I'll get mine set up for 3600 max and make sure the governor system functions well to hold down the overrevs. 

I haven't had a Tec apart yet, but I'd be interested to know how the lubrication oil gets into the Rod/Crank bearing journals, and also in the rod/piston pin areas. There must be holes in strategic positions. I imagine too large of holes... or too many would end up counter productive. Interesting to think about.

Thanks again!


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## 140278 (Aug 27, 2020)

lets remember there was a class action law suite back around jan.2009 over highly miss stated horse power ratings on out door power equipment engines . that was won . the settlement pretty much spelled the end of Tecumseh as shortly latter they went under. with the resulting split, LCT took the motors to china , Husqvarna grabbed up the peerless transmission side 
after that settlement they stopped rating by HP going to torque on the singles and lower hp using a different rating test on the twins which resulted in lower numbers


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## MX-Dad (Oct 24, 2020)

Thanks for that Captchas! I heard rumors about that happening, but didn't know the details. 

Still wondering about how the lubrication oil gets into the Rod/Crank bearing journals area, and also in the rod/piston pin areas rotating areas on these splash lubricated engines. There must be holes or ports in strategic positions. I imagine if the ports are too large... or too many, that might be counter productive. Interesting to think about.


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## 140278 (Aug 27, 2020)

if you look at photos of the conrods you will see either a cast on dipper or a bolt on dipper, depends on who makes the motor, tech and brigs bolton, kohler cast those pick up the oil from the sump,than by force push the oil into a rotation drilled hole near the dipper onto the crank .the splashing also lubes the rest of the motor. splash feed oiling is around since the dawn of motors, simple effective up to a certain point where to much rpm makes the oil foam to much starving it, 
when overhauling a motor one must pay attention to the rod it must go on correctly or the crank doesn't get any oil the rod gets hot and locks up


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## MX-Dad (Oct 24, 2020)

RE: ST1032. Hoping for some direction. FYI - I do intend to do the impeller mod as suggested, but in addition can anybody offer suggestions on up-sizing the drive pulley, and where to find or get one? Since it is overwhelmingly not recommended to increase the engine RPM, I'm thinking to increase the Impeller speed 10-20% to increase throwing distance. Certainly this will put additional load on the entire throwing drivetrain in heavy snow conditions, however I believe this could be easily managed by taking partial buckets during those times. As I stated before, I MUST have the throwing distance for my drive clearing situation. If I just cant get it with this machine, then maybe I'll have to jump ship to something else.

Thanks to all for your input.


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## deezlfan (Nov 8, 2017)

Have you even run this machine in the snow? Seems you have planned a lot of work for yourself without even trying it as is.


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## Shovel (Mar 26, 2019)

MX-Dad said:


> Thank you for the detailed reply. I cannot disagree and certainly don't want to rethink the Tecumseh engineering that has proven these engines over the years. I think I need to disagree with the comparison to an automobile or motorcycle engine lubrication system though. IMO they are not really similar. Auto systems use a positive displacement pump to lubricate. If the proper oil is used in a good condition engine, the rod and crank should never even touch each other when running. During operation there is a thin film of oil that isolates the parts. My Lexus runs over 3500 RPM at highway speeds out west for hours at a time, that combined with my very common redline acceleration habits up to 7000 RPM (with over 210,000 miles at this point) should make a good case. The dip solution that Tecumseh employs has proven to work, but I agree with you that there must be limitations, and your declarations make sense in my mind. I'll get mine set up for 3600 max and make sure the governor system functions well to hold down the overrevs.
> 
> I haven't had a Tec apart yet, but I'd be interested to know how the lubrication oil gets into the Rod/Crank bearing journals, and also in the rod/piston pin areas. There must be holes in strategic positions. I imagine too large of holes... or too many would end up counter productive. Interesting to think about.
> 
> Thanks again!


I did point out the difference in lubrication method ..we use a dipper (splash).
The advantage goes the the automobile with pressurized lubrication...Even then many automobile owners manuals do not recommend substained high speed operation while using 5/30 oil...We can't use 10/30 as we may have to start the engine in cold weather
These small engines do not like to be over speeded..in kart racing people will purchase aftermarket rods so the don't snap.. but they still kill them .. they will start to knock .. upon dissembly they resemble an oil starvation problem.
Tecumseh engines IMO are more sensitive to the oil level as well before destruction begins...I have seen old Briggs run low on oil.. Seize.. when it cooled off you could spin the engine again.. although it dragged.. shoot some oil down the cylinder and work with it for a while... Good to go.
Between the Old Briggs Old Kohlers and Tecumsehs ..I found the Tecumseh to be less tolerant to over speeding or low oil levels.
For what's it's worth my snow blower engine left the factory at 3450 RPM(Probably is allowed 3900rpm from the actual engine manufacturer)..I used it for the season at the factory setting of 3450..I have it set now at 3300 .
Some Toros are set to 3300 RPM although the actual engine manufacturer rates them higher..The concern is engine life vs performance..so not all snowblowers leave at 3600 rpm.
There are push mowers now that have the rpm set according to the blade size and there is a legal limit on blade tip speed




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## Shovel (Mar 26, 2019)

MX-Dad said:


> RE: ST1032. Hoping for some direction. FYI - I do intend to do the impeller mod as suggested, but in addition can anybody offer suggestions on up-sizing the drive pulley, and where to find or get one? Since it is overwhelmingly not recommended to increase the engine RPM, I'm thinking to increase the Impeller speed 10-20% to increase throwing distance. Certainly this will put additional load on the entire throwing drivetrain in heavy snow conditions, however I believe this could be easily managed by taking partial buckets during those times. As I stated before, I MUST have the throwing distance for my drive clearing situation. If I just cant get it with this machine, then maybe I'll have to jump ship to something else.
> 
> Thanks to all for your input.


I wouldn't increase my impeller speed unless I knew I had enough power to do it.
Laws of acceleration apply to impeller speed..it takes four times as much power with the impeller speed doubled while moving the same quantity of snow.
A ten percent increase will require 21 percent more power..you may find yourself having to lower your ground speed as a result..It also may be enough to really make the machine struggle in 'first' at the end of the driveway where the snow plow piles it up on you.
I have a split pulley set up..I gently ground down the filed the mating surfaces where the pulley meets in the middle.. I was only able to do this because my belt doesn't ride flush with the top of the pulley anyway...It's an MTD based machine that comes from the factory with a slower impeller speed..I don't remember what my final increase was..I think about eight percent..which will require close to 17 percent more power...My machine never had a bog issue..so I went for it..Also on the MTD based machines the auger screw ratio is less than other machines..The MTD machines have less angle on the flights so feed slower and the snow piles up in front of the machines.
If I can't run the higher impeller speed this year..I will just put a shim in between the pulley halves to space it back out.
Ariens usually have a fast impeller out of the box so it should do good..it might need the gaps closed on the impeller though with an impeller kit...Most members on here are happy with the distance the ariens machines are throwing snow... they usually do pretty good without speeding up the impeller..There are members though that do soup em up..bigger engines.. pulley changes..sort of like 'hot rodding'..it is not that they have to but just rather like the satisfaction of increased throwing distance. 



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