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Thread: Honda GX160 wont start

  1. #1
    Junior Member
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    Aug 2017
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    Honda GX160 wont start

    Hello all, i have a Honda GX160 engine giving me a bit of trouble. I recently changed the plastic governor gear and in doing so pulled the cam shaft out with the crank case during removal. The push rods and the cam followers fell down slightly but didn't drop out so i just pushed them back up.
    During reassembly i lined up the dimples in the cam and crank shaft ensuring that the dimples made contact on the power stoke of the cycle while turning the engine over by hand.
    I then positioned the piston to TDC and checked the valve clearances, setting the inlet to 0.006 and the exhaust to 0.008. After this i checked that the spark plug was igniting near the end of the compression stroke, which was fine. After replacing the gaskets i put everything back together and tried to start . Unfortunately i can not get it to start (it started fine before all of this meddling.) It backfires out of the exhaust and sometimes a puff of smoke from the carb but not as severe as the exhaust.

    I also cleaned out the carburetor with carb cleaner soaking the jets over night.
    Does anyone have an idea as to why this engine will not start? Any help will be much appreciated, thanks.

  2. #2
    Senior Member Footsfitter's Avatar
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    Re: Honda GX160 wont start

    Quote Originally Posted by JASONR View Post
    Hello all, i have a Honda GX160 engine giving me a bit of trouble. I recently changed the plastic governor gear and in doing so pulled the cam shaft out with the crank case during removal. The push rods and the cam followers fell down slightly but didn't drop out so i just pushed them back up.
    During reassembly i lined up the dimples in the cam and crank shaft ensuring that the dimples made contact on the power stoke of the cycle while turning the engine over by hand.
    I then positioned the piston to TDC and checked the valve clearances, setting the inlet to 0.006 and the exhaust to 0.008. After this i checked that the spark plug was igniting near the end of the compression stroke, which was fine. After replacing the gaskets i put everything back together and tried to start . Unfortunately i can not get it to start (it started fine before all of this meddling.) It backfires out of the exhaust and sometimes a puff of smoke from the carb but not as severe as the exhaust.

    I also cleaned out the carburetor with carb cleaner soaking the jets over night.
    Does anyone have an idea as to why this engine will not start? Any help will be much appreciated, thanks.
    Sounds like a timing issue. Check the key in the flywheel first. Next if you can remove the plug and get a probe on the top of the piston watch the rocker arms and turn it over to roughly see if you have the valves opening in the right strokes and roughly see where the flywheel magnet is in relation to the ign coil? Next I'd check the valve lash again- could a pushrod of sat up on a camfollower or something and be miles wide? Check the crank/camshaft timing again.

    After that if its still a non-runner, new spark plug? try a squirt of brake cleaner or easy start (watch it doesn't rip the rope out of your hands though) and see if it fires?
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  3. #3
    Junior Member
    Join Date
    Aug 2017
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    Re: Honda GX160 wont start

    Quote Originally Posted by Footsfitter View Post
    Sounds like a timing issue. Check the key in the flywheel first. Next if you can remove the plug and get a probe on the top of the piston watch the rocker arms and turn it over to roughly see if you have the valves opening in the right strokes and roughly see where the flywheel magnet is in relation to the ign coil? Next I'd check the valve lash again- could a pushrod of sat up on a camfollower or something and be miles wide? Check the crank/camshaft timing again.

    After that if its still a non-runner, new spark plug? try a squirt of brake cleaner or easy start (watch it doesn't rip the rope out of your hands though) and see if it fires?
    thanks for the response and advice. I managed to get it running by rehecking the cam and crank gear markings in relation to the magneto and reinstalling push rods and followers to ensure they were not sat up on the followers as you mentioned. After reassembling she fired up immediately.
    However there is a subtle popping from the exhaust now though so I'm assuming I have my valve clearances slightly out?
    Thanks.

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