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Honda GXV620 engine - uneven running

Discussion in 'Mechanic and Repair' started by steheap, Apr 6, 2013.

  1. steheap

    steheap LawnSite Member
    Posts: 10

    I have a 6 year old Hustler Fastrak mower with Honda GXV620 engine. Last season it was sometimes running unevenly and lacking power - unsteady noise from the engine - and would slow and almost stop with the blades turning on an incline. I changed the air filter and foam filter and that seemed to fix the issue. It then started again right at the end of the season. I could simply remove and replace the same filter and the next time it would be OK.

    Over the winter, I replaced the air filter, fuel filter, spark plugs, but when I had completed all that, the first time I started it, it still stuttered, but I put new gasoline in, and the next start was fine. I did a bit of mowing and put it away. This morning - same thing - uneven, lacking power.

    I hadn't checked the spark plug gaps, and so I took one out, checked it (OK) and put it back in. Next start - it was fine and I mowed for an hour.

    I'm not confident that I have actually found the issue though - it almost seems to be that doing something around the engine fixes it, but after a rest, it is back to low power again!

    Any ideas?

  2. herler

    herler LawnSite Fanatic
    Posts: 5,144

    You might try...

    Sometimes fuel lines erode and corrode on the inside of the tube where the eye can't see, and little pieces of dirt and rubber float down-stream and in other ways create obstruction... Can't say this will fix the problem but it's a cheap fix along the same lines of what you have been trying, I'd see about replacing the fuel line(s).
  3. steheap

    steheap LawnSite Member
    Posts: 10

    That sounds interesting - the way it improves when I do "something" makes me think this is related to dirt in the system somewhere.

    Not sure about fuel lines - wouldn't this dirt collect in the fuel filter and I've just changed that? I suppose there could be dirt in that switch on the Hustler that moves the fuel line from one tank to another and there is a blockage there?

    Does the carburettor on one of these sort of engines need cleaning after 6 years?

  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023


    Your lucky if you've made it that long without cleaning the carb.....

    The most common "something" your repeating is starting the engine and turning it off......

    Here's my theory as to what's happening;

    There's possibly a piece of trash floating around in the float bowl, When the engine is running fine the trash is clear of the main jet. Bouncing across a yard this trash can float into the main jet port reducing fuel delivery, Once the engine is shut down the suction on the main jet stops and the trash moves clear of the jet until it works it's way back into the path.

    Some may be thinking far fetched, But I've seen and found this more than a couple times.

    Also found this in a few carbs;


    This is a gel substance that accumulates in carbs due to this sorry ethanol fuel and moisture buildup from storage/sitting, Once this crap was cleaned out the units ran as normal again.

    I'd suggest a carb clean and see how it runs afterward.......

    IRRITECH LawnSite Senior Member
    Posts: 931

    Also check to see if you have stuff floating around in the gas tank. Suction can draw it to the inlet and once you shut it off it floats away. Had this happen on a walkbehind. Mower would run fine for a while and then cut out. would start back up after a bit. Screen at the bottom of the tank was broken and debris would clog it up. Cleaned the tank and installed a new screen, no more problems.
  6. steheap

    steheap LawnSite Member
    Posts: 10

    Great ideas - thanks.

    Is that bowl under the carburetor something an amateur can remove and clean, or is this the time to find a proper maintenance person?

  7. WillsLandscape

    WillsLandscape LawnSite Member
    Posts: 130

    It's pretty easy to clean, but if you're not sure, here's a link to a video that I recommend to watch to learn what to do and how to do it.


    It's the same style float carburetor, just different engine brand. This particular mechanic posts a lot of videos that are really interesting and informational. Hope this helps!!

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