Smoke Coming Out of Muffler - Honda GXV120‬

GAVolunteer

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Jun 28, 2013
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Honda HR214-SX
Engine: GXV120 – 118 cubic cm

When I started the engine, a lot of white smoke was blowing out of the muffler. The mower/engine also made a “loud noise”. I wish I could better describe the noise, but because of the smoke, I quickly shut off the engine. I did not have enough time to determine if the noise was internal to the engine or if it was related to other mower parts.

I removed the cylinder head and checked the head gasket. I did not see any “burn marks” on the head gasket. But I did see a couple of areas where part of the film that covers the gasket was missing. (see attached pictures). What I don’t know is if the possible “damaged” areas of the gasket were caused when the gasket was removed (which often happens) or if that had become weak area of the gasket allowing oil into the cylinder. The part of the gasket around the cylinder looked in great shape which makes me doubt that it was the head gasket, but I could be wrong.

There was a lot of carbon buildup on pistons and head which I cleaned.

The only other thing I can think of is a bad or broken piston ring. Is there a way to troubleshoot a bad piston ring without taking the engine apart? Any other troubleshooting steps to determine the cause of smoke coming out of the muffler?

Thanks
 

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  • Valves.jpg
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bertsmobile1

Lawn Royalty
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Repace the head gasket.
Rings can not go bad while the mower is sitting going nowhere unless it is under water.
While sitting there, it has ether leaked oil into the cylinder then down into the muffler or it has leaked fuel into the cylinder which caused a hydraulic lock, which in turn blew out the head gasket.

The other big cause of smoke is overheated oil the last time you used it which bcame too thin and gets sucked into the cylinder as the engine cooled down.
 

GAVolunteer

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It turns out the problem was a bad oil seal on the crankshaft under the flywheel. Oil had coated the engine and muffler and caused the "smoke".

I never determined the cause of the mysterious noise. I was able to find someone who had an identical mower. He plans on taking the best parts off both mowers and make one good mower.

Thanks for the help and suggestions.
 

motoman

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GA, You dodged a big one there, and good on ya. My Intek smokes off muffler on start up , but it's due to a leaky valve cover sitting right over the muffler. I need to get off my duff and fix it.
 

hkmiller

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It turns out the problem was a bad oil seal on the crankshaft under the flywheel. Oil had coated the engine and muffler and caused the "smoke".

I never determined the cause of the mysterious noise. I was able to find someone who had an identical mower. He plans on taking the best parts off both mowers and make one good mower.

Thanks for the help and suggestions.

I have the same issue as you with the leaking oil seal, but my gxv120 has smoked from day 1. It is now smoking more. I replaced the oil seal but oil is still leaking by the seal. So I am going to replace the piston rings.
 
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