# Nearly impossible to start, but runs fine. Coil?



## Glove (Feb 8, 2015)

I have a 15 year old Murray snow Thrower (model # 622505) with a Tecumseh HSSK50-67394S that I had professionally tuned up about 5 years ago. I’m very good about using Stabil in the gas, and at end of each season I drain the gas tank, drain the carburetor bowl, coat the cylinder with a teaspoon of oil, grease the zerks, and change the oil. And with a new plug put in each winter, it fires up reliably and easily on the first pull, as it did this winter. But after running fine earlier in the season, last week it just would not start (after a month of non-use, and my wife had put gas in the tank without Stabil). So I drained the tank and the carburetor bowl, filled with fresh gas from the pump (with Stabil and with one ounce per gallon of Seafoam) but it still wouldn’t start. Finally, after 10 minutes of heroic and exhausting trying, I got it started. And it ran fine – no sputtering, stalling, surging. I ran an entire tank of gas through without a problem, and figured we’d be all set. But after shutting it off, despite a warm engine that had just been running, it wouldn’t start again….at least it wouldn’t start without very heroic pulls multiple times (despite a very warm engine). After 10 minutes of trying to the point of near exhaustion, I got it started again. I confirmed this problem by again shutting it off, and having to work like a dog to get it started. Once started, it runs fine. I never had problems like this – even earlier this season it would always start on the first pull. 

So I suspected a problem with the carburetor. I tried Mechanic in a Bottle and precisely followed the Youtube directions to the T. But after this overnight treatment it still wouldn’t start… Ten minutes of exhausting pulls later, I got get it started, and ran an entire tank of gas to better dilute/flush out the Mechanic in Bottle and get more Seafoam through the carburetor. But still, I again can just barely get it started. After pulling/pulling/pulling to start it, if I check the plug, it’s wet. (BTW, I already tried a new plug). I can see a spark when I ground the plug to the engine housing and pull the starter – but I can’t tell if the spark is appropriate “strength” or not. So on to the questions:

Is this more likely a carburetor problem, or an ignition problem? (Again, the engine runs fine once I can get it running, but it’s nearly impossible to get it running). I don’t think I trust myself to rebuild a carburetor….I’d have to take it in to the shop and fork over the big bucks they charge around here.

To test the coil, which ignition tester do you recommend I purchase (Will this inexpensive one from Amazon do the job of confirming the coil is fine as well as demonstrate that the coil is bad?) 

http://www.amazon.com/Neiko-Tools--Line-Spark-Tester/dp/B000MHNDSM/ref=sr_1_7?ie=UTF8&qid=1423361958&sr=8-7&keywords=ignition+spark+tester

I’d certainly feel comfortable changing the ignition coil (about $45 for the part) if that were proven to be the problem.

Thank you for your thoughts
Glove


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## RoyP (Oct 16, 2014)

I would say your problem is a dirty carburetor. I'm not a fan of doctor in a bottle. I recommend that you go to NAPA get a gallon can of carburetor cleaner....clean by soaking the complete carburetor with jets removed in the cleaner, include the jet needle valves. You can see a difference in the carb, I really think this will solve your troubles. Also check to see if your machine can accept a elec starter..


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## db9938 (Nov 17, 2013)

I concur on the carburetor needing a cleaning.


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## Normex (Feb 21, 2014)

Glove said:


> I have a 15 year old Murray snow Thrower (model # 622505) with a Tecumseh HSSK50-67394S that I had professionally tuned up about 5 years ago.
> To test the coil, which ignition tester do you recommend I purchase (Will this inexpensive one from Amazon do the job of confirming the coil is fine as well as demonstrate that the coil is bad?)
> 
> I’d certainly feel comfortable changing the ignition coil (about $45 for the part) if that were proven to be the problem.


 You certainly have a handle to keep your Murray in shape, of course the first culprits as you correctly point out is gas and spark, I am inclined like you towards the spark and it would be fairly cheap to find out with this spark checker pointed out by members here, it will show you the spark quality being bright blue which is indicative of a good coil but you may have to test it also when you have a hard start situation.
Here's the part: 



 
After testing and if your coil seems in good condition, I would definitively check the valves. Intake should be .008 and exhaust at .012

Check the vid of Donyboy explaining how:




 
Good Luck and let us know how it turns out.


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## CarlB (Jan 2, 2011)

another thing to check is to make sure the primer is working. It doesn't sound like your problem here but it could be. Sometimes the hose that goes to the engine get a hole rubbed in it and it causes the primer not to work.


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## AL- (Oct 27, 2014)

maybe take spark plug out and dry well , squirt a small amount of gas down plug hole, put plug back. Then see if it will fire up with just 3 or 4 pulls. If it does your ignition might be Ok. With my 4HP Briggs and Stratton I can take the shroud with pull assembly off with 3 bolts and with some fine 400 grit sand paper clean rust off flywheel magnet and end of coil where the gap is quite easily without disturbing coil.


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## motorhead64 (Dec 15, 2013)

Hi Glove,
Welcome to the Forum.
Coil problems do not improve with exhaustive attempts to start. A dirty or partially blocked carb instantly alters your air/fuel mix causing hard start/restart issues. MH


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## Glove (Feb 8, 2015)

Thanks everyone for your interest, time and help. One other comment to make is that I have noticed something during my heroic tries to start the engine - the engine doesn't backfire or sputter when I pull the starter, but I notice that on some pulls of the same amount of force turns over the cylinder 6 to 8 times -- almost like I had pulled harder. I suspect "tiny explosions" in the cylinder (not really audible) are helping push the cylinder. During those times I feel that only if I had an electric starter to deploy for longer, it would have started. But it seems that in thinking spark versus fuel/air as me problem, there is no reason to think that the spark would be "stronger" once the engine is running. Presumably there is no ignition coil problem or magnet problem that would provide insufficient spark in my pulls, but provide sufficient spark once up and running. I'm telling you, once it starts, it performs like a champ...no sputtering under load, etc.

Based on the comments from everyone, I've done the following:
Rechecked the priming bulb - it squirts gas very well into the carburetor
Drained the gas (yet again) and used a 1/2" wrench to remove the screw/jet holding the bulb in place. The bowl had no varnish, and the screw/jets were completely clean - no gunk whatsoever. Could easily see day light through the larger hole. Used a tiny wire and carb cleaner to ensure that all passages are clear. The rim of the bowl and the bowl gasket had a smidge of gunk....carefully cleaned this with carb cleaner. Perhaps the "deeper workings" of the carburetor are still gummed up because mechanic in bottle easily reaches the bowl and screw/jet but not deeper. And hard to believe that just some minor bowl rim gunk would create an air leak in a way that that would make it impossible to start, but once started, run flawlessly.

So based on everyone's comments, I plan to do the following:
I will not empirically purchase an ignition coil although I will order the ignition tester anyway. 
I will assume a carburetor problem and take off the carburetor and carefully dismantle/clean myself, or alternatively take to the local shop where I would have to wait a week or two, and pay with one of my extremities.
If after this it STILL doesn't start, then I'm at a loss - I won't be sure if I screwed up the carburetor settings/reassembly, or rather, assumed that this is some crazy electrical problem with ignition coil, magnets, grounding. At any rate, I'll keep y posted. 

Again, thanks for everyone's help and interest. 
Glove


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## motorhead64 (Dec 15, 2013)

Glove,
When you hear little "pops" that sound like she wants to start, reduce choke by a click and continue starting. I think she will fire. MH


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## db9938 (Nov 17, 2013)

I would also check to see if the plug is wet, at the point when you hear the sputters of life. If it is wet, then it is not the carb. That would most likely rule that out, and would certainly make me lean towards spark and your coil. 

Other thoughts, and not what I would normally recommend, but if you consider just the diagnostic fees of you local shop, you could go ahead and purchase the coil. Even if it ends up being the carb, you can buy those pre-set, online. Just bolt, connect and go.


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## RoyP (Oct 16, 2014)

db9938 said:


> I would also check to see if the plug is wet, at the point when you hear the sputters of life. If it is wet, then it is not the carb. That would most likely rule that out, and would certainly make me lean towards spark and your coil.
> 
> Other thoughts, and not what I would normally recommend, but if you consider just the diagnostic fees of you local shop, you could go ahead and purchase the coil. Even if it ends up being the carb, you can buy those pre-set, online. Just bolt, connect and go.


My 1969 5HP Tecumseh gave me fits when starting. I did order a replacement carb online, bolted it up to machine and she fired right up. Never had starting trouble with it after that. That's an option.


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## Normex (Feb 21, 2014)

Glove while all the previous posts are valid attempts to get you going maybe you should try with the basics again as you wait for your ignition tester.

To get the spark out in the equation you should try what Al mentioned above but for that your engine has to be fresh to start in other words your spark plug dry and cylinder void of any gas then after putting some gas through the plug hole the engine with a good spark has to make an attempt to start if not the carb might be the issue and then the ignition tester should show a bright blue spark to eliminate that issue as well. We're digging at the bottom of the barrel but it is always primordial to cover the basics on both fronts. Good Luck


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## Glove (Feb 8, 2015)

Okay, here's the follow up and end of the story for my snowblower problem. (Summary of problem: Murray with Tecumseh HSSK50 -- always maintained well, ran like a gem earlier this season, but then suddenly became impossible to start. It would start only after heroic starting attempts e.g. 10 minutes of pulling the starter cord. Once started, it would run like a champ -- no stalling even under load. But upon turning it off, it would take 10 minutes of heroic attempts to start it.)

CarlB gets the prize . Based on his advice -- which I didn't read carefully enough  -- I checked the primer bulb for defects as follows -- I emptied the carburetor bowl and then pressed the primer button and observed new gas deposited into the bowl. It seemed to work fine, and so I incorrectly assumed that I had crossed this potential problem off the list. But after I removed the cover to remove the carburetor, I noticed that the rubber primer hose had a 1 inch longitudinal defect. (I think the muffler melted it.) Picture attached. Since I had already pulled the carburetor, I checked it -- not a trace of gum/varnish. But I cleaned it anyway. Reassembled -- new hose for the primer -- and WHAM! It starts on the first pull just like it always did. Hooray. I used a zip tie to keep it close to the fuel line and away from the muffler.

The very minor downside is that I ordered a new ignition coil with expedited (and expensive) delivery ($18 + $12 expedited delivery), a new carburetor ($18 + $12 expedited delivery). I'll return them and then only be out the shipping both ways -- perhaps $35 in total. The most important thing is that we're up and RUNNING!!  Thank you all! I'm in Boston we are really in dire need for this to be working.

Thanks to all for your time, interest, and input.

Glove


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## RoyP (Oct 16, 2014)

that's good news.......now to melt your snow piles !!


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## db9938 (Nov 17, 2013)

Well, it's good to hear that you got it up and running.

When you get a chance, post up some pics of the piles.


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## classiccat (Mar 1, 2014)

Great news Glove!!! Keep that Tec alive to fight another day man!

Thanks for checking back!!!


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## scrappy (Dec 7, 2014)

classiccat said:


> Great news Glove!!! Keep that Tec alive to fight another day man!
> 
> Thanks for checking back!!!



Agree! 

Always good to have a spray can of starting fluid (ether) around. Always a can or two here, even in the summer.


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