# Honda GCV 190



## RKDOC (Jun 20, 2006)

On a lawnmower with the above engine it will start but pops out the carburetor and has low power. I pulled the rocker arm off and checked the valves. They seem to be fine and properly adjusted. I checked the timing and the marks on the camshaft pulley are lined up with the housing when on TDC. This would make it appear to be in time.

The mower was mowing just fine when it lost power. I shut it down and brought it into the shop. That is when it started poping through the carburetor. I have also checked the gap on the pickup coil.

Any suggestions what would cause the backfire through the carb?

Thanks in advance for all your help and advise.

P.S. The engine had good compression and a new air filter.


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## 30yearTech (Sep 14, 2006)

A fouling spark plug will make an engine backfire, so even if the plug looks good, I would try a new one.


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## dawgpile (Apr 28, 2008)

Did you hit anything with it? Backfiring can be caused by the timing being off, which in turn can be caused by a sheared or partially sheared flywheel key. If you don't know the history of the machine, I'd recommend pulling the flywheel and verifying that you have a good key as a first step.

Let us know what u find!


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## RKDOC (Jun 20, 2006)

I forgot to mention. I have pulled the fly wheel and the key is good. A customer brought the mower in with a stuck valve. He did not want to pay the price to fix it so he gave me the mower. I took it down and replaced the valve. Put evrything back together and use it to mow my lawns. It was running great, then one time it just lost power. Thats were I am at now. I will change the spark plug and try that.

Thanks for the replies.


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## wheelerman (Jul 19, 2007)

Is the valve cover pushed in from hitting something?


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## RKDOC (Jun 20, 2006)

Thanks for all the helps. 30 year got it right. A new spark plug and it runs great. It is surprising the problems a perfectly good looking spark plug can cause. Thanks again for all the help.


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