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20hp Honda GXV620 No Spark

Discussion in 'Mechanic and Repair' started by lt1nut, May 4, 2012.

  1. lt1nut

    lt1nut LawnSite Member
    Posts: 6

    I have no spark on the Driver's Side on my Honda Twin in my ztr.

    I have:
    • Tested spark with known good spark plug against a known good ground
    • Replaced the coil and swapped them side-to-side to rule out receiving a bad new one
    • Swapped spark plugs
    • Unplugged the diode wires to test it
    • Replaced the diode unit anyways (I HATE throwing parts at something, but...)
    • Tested compression

    What am I missing?

    Why can I fix cars, semi-trucks, farm tractors, boats, etc but small engines throw me for a loop?:confused:
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Posts: 2,231

    I seem to recall that the ignition coils on a 620 are not interchangeable, side to side. I believe they are two different part numbers. The guys with the brass ones will call me on it if I'm wrong.
  3. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,955

    Dutch is right. They are different and not interchangeable.
    Posted via Mobile Device
  4. lt1nut

    lt1nut LawnSite Member
    Posts: 6

    Thanks; when I ordered them there were new part numbers - both the same as what used to be the passenger side. I'll have to double-check on that again, along with at the dealer. They look the same physically but one gets mounted upside-down compared to the other.

    Again, THANKS!
  5. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Posts: 450

    Yup, coils are cylinder specific .
  6. lt1nut

    lt1nut LawnSite Member
    Posts: 6

    Both coils on it now have an "L" printed on the coil wire, one has an orange paint dot on the coil body, the other a blue paint dot, and both have the same length coil wire. One looks newer than the other.

    The old (although it looks new) coil has an "R" printed on the coil wire, an orange paint dot on the coil body and a small blue paint dot where the diode wire plugs in, and the coil wire is shorter than the other two (obviously for the right side). It was in the bag that I received the new coil in, Honda part # 30500-ZJ1-845; I wonder if the bag had the wrong coil in it. I managed to lose the receipt but highly doubt I ordered two coils - that wouldn't be normal for me.

    I started working on this last fall and have switched the two "L" coils around so many times that it isn't funny - I don't remember which is supposed to be the new one. What really confuses me now is that I've been getting spark on the right side only but with both coils marked with the "L" on the coil wire, never any spark on the left side of the engine no matter which of those two coils are installed there. The mower runs smooth on one cylinder but obviously has barely enough power to very slowly cut grass, in addition to dumping gas past the rings and into the crankcase. (I've installed a low psi electric fuel pump to take the pulse pump out of the loop on that problem, just in case, even though the pulse hose was dry.)

    I'm going to go out, put the "R" coil on the right side and the a "L" coil on the left and see what happens....

    Again, THANKS for the help - I usually ain't this dense!
  7. lt1nut

    lt1nut LawnSite Member
    Posts: 6

    Figured I'd post what's up, even though it ain't very flattering to me. I put the old coil on and it runs just fine, minus two-cycling every once in a while but that might be due to wanting new plugs. Most I can figure is that it was the diode. And that the place I got the coil from has the right and left backwards on the diagram - when facing the carb "R" is on the left side and "L" is on the right side is the correct way.

    Thanks for the help and rattling the stones in my head about two different coils!

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