# Ariens (Bolens) Tecumseh Motor Compression



## neuralgroove (Feb 16, 2017)

I have an older snowblower that last year at the end of the season blew the connecting rod. I disassembled, ordered a new piston and connecting rod, reassembled and ran (in the garage, there was no snow at that point). Its been sitting since then. I just tried to run it, and it starts fine, idles a bit rough, but when I engage the auger, it slows, and then when I try it in actual snow, it dies.

There is air blowing out from around the top of the block (as well as from the exhaust), so I suspect that the head gasket is not effective anymore (I did not replace it).

1) Would that cause this problem?
2) Is it worth it to get some material to make my own gasket?
3) is there some kind of product to seal the current gasket?
4) Should I just break down and order a new gasket for this senior citizen of a snow blower?

She's old, and it has saved me a lot of times (think 1/4 mile driveway in central alberta), so I don't want to give up on her. Any advice would be greatly appreciated!


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## 43128 (Feb 14, 2014)

just buy a new gasket. im asuming you have an h50, h6o0, or h70. h50/h60/h70 gaskets are dirt cheap, only 5 bucks online 10-15 if you go to a dealer. no gasket material i know of that you can make a head gasket from


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## Dave C (Jan 26, 2015)

Also be sure to follow the proper torque sequence - 50 inch lbs at a time until you get to 200 in lb.


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## RedOctobyr (Mar 2, 2014)

Air blowing out from around the top of the block? That sounds like a head gasket to me. But wow, presumably a big leak in the gasket! And I'm not sure if it would explain a leak at the exhaust. 

Like they said, buy the proper head gasket, and torque it as-directed, using a torque wrench. Put anti-seize on the threads, you don't want those bolts to lock up. 

If you have an electric starter, you might be able to crank it for a few seconds and see if you can feel where the air is coming out. You could then remove the spark plug, and check it with the electric starter again. If they air isn't coming out that time (because there's no compression), then that would likely indicate the head gasket. 

Hopefully the block isn't cracked. A blown head gasket in an L-head engine (vs OHV) should primarily reduce available power, due to lost compression. Though I'd expect the engine to possibly be harder to start, if it's a big leak. You're losing compression, at the same time that the compression release is probably active. Is it noticeably easier to pull-start now? If you have a compression tester, you could do a compression test. You could also remove the little side cover and check your valve clearances, to make sure they're closing fully. 

But pulling the head off is pretty easy, and a good check. Make sure you scrape off any old gasket material fully (if it's a graphite-based gasket), using something soft that won't scratch the sealing surface. A plastic putty knife, a wooden paint stirrer, etc. Preferably not something steel, until you're very gentle/careful. While you had the head off, I'd also take a look at the valve sealing surfaces, especially if the head gasket looked OK, or didn't have an obvious mark at a leak.


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## skutflut (Oct 16, 2015)

Air blowing around the head could be from the fan on the fly wheel forcing air around the engine shroud to cool it. That's normal. If the head gasket was blown that badly it wouldn't run. That said, always change those critical gaskets when putting and engine back together.

Did you reassemble the carb linkage and governor linkage exactly as it was before? Everything needs to be just so using the same holes as original or the governor wont work properly to keep the engine at the desired speed under varying loads. Also check the gaskets on the intake manifold to make sure there are no air leaks there which would cause power problems with unauthorized air getting sucked into the intake. I assume you got the cam shaft in and line up the timing marks exactly as being a tooth off there will cause problems. 

Did the lifters fall out when you removed the cam shaft to get at the connecting rod? If so, they need to go back in the same place they came from, or your valve clearance might be messed up and one of the other might not be not opening or closing fully. Was the governor gear Ok and did it go back in OK so that the plunger pushes on the rod inside the engine that extends to the outside to operate the governor lever? 

Check the valve clearance. As Red mentioned, while changing the head gasket, check the valves and make sure they seat properly and you cannot rotate them by hand. I would be inclined to lap the valves as long as the engine was open anyway, since it it an older engine and wear happens.


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