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Honda Harmony Rider problem

Discussion in 'Mechanic and Repair' started by leadfoot4, Jun 10, 2008.

  1. leadfoot4

    leadfoot4 LawnSite Member
    Messages: 9


    I'm new here, and in need of some advice. I have a Honda Harmony 1011 riding mower (hydrostatic drive). It's 7 years old, and has been fairly well maintained. Recently, however, it developed an annoying problem, and I'm hoping to find an answer, as the dealer has never seen this before.

    Long story short, after the engine has been running for a while and is fully warmed up, it doesn't want to re-start if I have to shut it down for any reason. From a "cold" start, it fires right up.

    The spark plug is new this year, although the old one looked good; the gasoline is fresh; the air filter clean; no trash in the fuel line screen; the carb float is freely moving; the oil is fresh (changed annually).

    The only change from last year, and possibly a clue to the problem, is I removed the starter over the winter, as it seemed to be getting "sluggish" toward the end of last summer. I did have to remove the flywheel and ignition module in order to get at the starter. I put a few drops of oil on the motor shaft of the starter, and freed it right back up. I reassembled everything as carefully as I could, and I think I got the ignition module back in its original location, based on screw marks from the initial assembly, and some "witness marks" that I made during disassembly.

    Would anyone have any idea of what might be wrong?

    Thanks for any input you could provide......
  2. leadfoot4

    leadfoot4 LawnSite Member
    Messages: 9

  3. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Can you post the model# and spec#s of your engine, please.
  4. leadfoot4

    leadfoot4 LawnSite Member
    Messages: 9

    The mower is an H1011 HSA. According to the owner's manual, the engine is a GXV340K1, 11 hp, 337 cc unit.
  5. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Ok first just double check the plug that was installed Honda recommends NGK BPR5ES or DENSO W16EPR-U both gaped at 0.70-0.80mm or 0.028-0.031in.

    The ignition coil should be gaped between the coil and magnet on the flywheel @ 0.010in or a good business card will usually do.

    If all that checks out the next thing I would do is have a valve adjustment performed by your dealer the Honda manual recommends annually or every 300hrs. and the spec is
    Intake: 0.15mm or 0.006in
    Exhaust: 0.20mm or 0.007in

    If this adjustment is too far out of spec then it can give a hard start issue once the engine is hot.
  6. leadfoot4

    leadfoot4 LawnSite Member
    Messages: 9

    Thanks very much for the advice. When I reinstalled the ignition module, I used a shim of some sort, but I don't remember exactly what I used. I doubt, however, that I got it quite as close as 0.10", probably closer to 0.15-.020". I'll also check with the dealer about getting the valves adjusted. I had no idea that this was required.
  7. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    No problem, don't know if after 7 years you still have your owners manual but if not this is a link for the info for your motor.


    just do a search for your engine under the product manuals tab on the left.
  8. leadfoot4

    leadfoot4 LawnSite Member
    Messages: 9

    I went out this AM, and checked the ignition module as you suggested. I had two business cards to choose from, one was about 0.008" and the other was around 0.012", as measured with my verniers.

    I started with the 0.012" card, and set the ignition module spacing with that. As is normal, it fired right up, but was somewhat rough running. I gave it 20-30 seconds to warm and "clear out", but it remained rough. (I've been messing with cars for 40 years, and although I understand ignition timing with them, I never realized that a single cylinder engine had the same reaction to incorrect timing.)

    I then shut down the engine, and got the second card out, and used them both to set the gap, however I pressed somewhat firmly while tightening the module in place. I probably compressed the cards to maybe 0.015" or so. Again, it fired right up, but this time ran a lot smoother. I headed out on the lawn, and ran for about 30 minutes, until it started raining, and I had to stop.

    I got into the garage, shut it down, and tried to restart it. It did, reasonably well, so I tried again about 10 minutes later. At that point, it really didn't want to go, and it just popped back a few times through the muffler. I pulled the plug, grounded the plug to the cylider head with a piece of wire, and cranked it over. It appears that I'm getting spark. It looks like I'll have to get the valves adjusted....Do you think it could be done at home, by a reasonably talented wrench? I ask this because my Honda dealer is way on the other side of the county....

    Once again, thanks for your advice!
  9. VT_Grassman

    VT_Grassman LawnSite Member
    from Vermont
    Messages: 56

    What are you using for fuel? I have seen some of the ethanol blends cause these kinds of symptoms. (This is not to say that if your valves have in fact never been adjusted, that you should ignore that advice.) I would definitely think you can do the valves yourself.

    It could also be possible that when you had the carb apart that you changed the float level adj. a bit. What may be happening is that when this engine is HOT, you are getting an slight flooding/rich condition. Check to be sure the float is a bit higher than level when the carb is held inverted (float upward). The needle and seat may also be worn and allowing more fuel into the carb than there should be. There is a fair amount of vibration there and I don't know how rough your yard is so the needle/seat could be worn.

    I just can't see how you could have moved anything enough to affect timing based on what you are telling us -
  10. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Popping through the muffler shows the exhaust valve staying open too long, if it was through the carb then it would be the intake. I would think you should be able to perform this all you really need are a good set of automotive feeler gages and the tools to remove the valve cover and loosen and re-tighten the rocker arm lockers. The motor should be cold and the engine @ TDC.

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