# Honda GX140 Help! Please!!!



## David Baricevic (Aug 25, 2017)

Hello to all, I have been reading a few posts (a lot really) and this had led me to this site so I am hoping someone on here will be able to help me.
I picked up an old Honda GX-140 motor on a reel or cylinder mower of a friend who hadn't been using it for quite some time.
I attempted to start it and it would start and run sometimes but was very hard to get going.. it wouldn't idle and run like crap. I initially suspected bad fuel - sitting to long so I stripped the fuel tank cleaned it out thoroughly and cleaned and checked the fuel filter. I could get it to start again - very hard but it was still running like crap. 
I moved onto the carby, I cleaned all the jets carefully using my welding tip cleaners and sprayed carby cleaner all through it and blew it out with an air compressor - no better. I ordered a new carby of the internet and installed it - a small improvement but still hard to start. Occasionally when I got it running I noticed the governor was hunting and so I moved onto the springs. Checked and replaced all governor springs and then setup the governor arm again as per the manuals and instructions I found. This only achieved one thing - It would rev like crazy and wouldn't self regulate. I then replaced the spark plug which looked good but changed it anyways. The machine now start a lot better but backfires like crazy and still wont idle. Again if you touch or move then governor arm manually it will rev like mad. I then suspected that the backfiring could be caused by timing issues so I removed the flywheel and checked the woodruff key and coil air gap - All intact appears to be fine and put it back together. Still misfires badly and blows flames out the intake and exhaust and again when you touch the governor it will rev like mad. I suspected the valves may now need checking so I pulled the rocker cover and inspected - they were close to spec but I made a small adjustment to intake and inspected it make sure it wasnt sticking opened and lubed it up a bit. Still misfires. I then compression tested the motor 80psi.. I am thinking next step is to remove the head and check the valve seat? Anything I have missed surely it has to be something simple.


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## nbpt100 (Jun 1, 2015)

I believe compression should be 100 psi or higher. But I doubt that explains your backfiring. the surging may be from being too lean. Some people open up the main jet just a a few thousandths of an inch to make the mixture richer.

the exhaust valve may be not be closing all the way. Are you sure you inspected the clearance properly. The engine must be just a hair past TDC when you inspect the valve clearance... Is this a OHV engine with adjustable valve clearances? Or is it a flat head with fixed clearances.
also check the valve guides If the exhaust guide is worn the valve may not always be seating. What kind of gas are you using? 87 octane?


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