Forum Discussion

Kayteg1's avatar
Kayteg1
Explorer II
Jan 25, 2018

Generator giving single spark only?

It is Generac Impact 36 inverter generator.
BOY ! I hate those electronic controllers.
After spending small fortune on board that failed, now the board seems to be working, it is cranking the starter, but I observe single (strong) spark on first turn and nothing after.
I swap good working coil and it is the same.
I found capacitor bolted to the wall, who show some overheating. No marking on it, but found the rating in manual and found identical on ebay to replace it.
Still having long troubleshooting manual - the issue is not covered.
So what are the chances that new board or new capacitor are bad?
Or can it be something else?

8 Replies

  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Jan 25, 2018
    MY BAD. What I took as capacitor, has to be resistor.
    No marking on it, but diagram shows R1 as 1 ohm. 50 watts.
    I copied ignition part from Generac diagram. I don't see capacitor on it and I did not see it on the unit itself.
    The service manual I found on the net, with hundreds of pages provide extensive troubleshooting help, yet my issue is not covered.
    So can that be "famous" electronic board (just replaced with new)?
    The old board would not crank the starter at all.


    Click For Full-Size Image.
  • westend's avatar
    westend
    Explorer
    Jan 25, 2018
    So how do I test capacitor?

    Without power in cap: Put multimeter in high ohms range and leads on the two wires from the cap. Your meter should slowly swing from 0 to infinity.
    Some meters have a capacitance mode but most don't go high in value. What is the value of the capacitor? You could also list the Mfg (someone may have turned up a bad cap with that name).

    Maybe I missed it, what instigated the board replacement and all the rest? Getting back to the "simplest may be the problem", you have checked that you have good battery power and all connections are continuous?
  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Jan 25, 2018
    Like I said - coil was ruled out as I have 2 confirmed working.
    I put new plug as well.
    So how do I test capacitor?
  • centerline's avatar
    centerline
    Explorer
    Jan 25, 2018
    on most small engines, that symptom would indicate a bad coil.... thats the thing that the spark plug wire originates from.
    if it were me, I would replace them both at the same time...
  • GordonThree's avatar
    GordonThree
    Explorer
    Jan 25, 2018
    Capacitor from eBay could be any old junk sealed in can and sold as a legitimate part.
  • westend's avatar
    westend
    Explorer
    Jan 25, 2018
    ....can it be something else?
    It seems like it can always be something else. :)
    I would check plug wires, coil connections, plug integrity. The last can be difficult to diagnose. Years ago, every garage seemed to have a plug tester/cleaner. Now, we just replace them.

    If you're getting intermittent spark and the board seems to function in every other aspect, the capacitor can sure be the problem. Do you have a meter with capacitance test function?

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