cancel
Showing results for 
Search instead for 
Did you mean: 

Generator giving single spark only?

Kayteg1
Explorer II
Explorer II
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 8

DiskDoctr
Explorer
Explorer
Do the other stuff above. And check your generator ground 😉

Kayteg1
Explorer II
Explorer II
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.

eHoefler
Explorer II
Explorer II
Condensor is bad
2021 Ram Limited, 3500, Crew Cab, 1075FTPD of Torque!, Max Tow, Long bed, 4 x 4, Dually,
2006 40' Landmark Mt. Rushmore

westend
Explorer
Explorer
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?
'03 F-250 4x4 CC
'71 Starcraft Wanderstar -- The Cowboy/Hilton

Kayteg1
Explorer II
Explorer II
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
Explorer
Explorer
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...
2007 M-3705 SLC weekend warrior, 5th wheel
2014 Ram 3500 CC/LB, 6.7 Cummins
2004 Polaris Sportsman 700
2005 Polaris Sportsman 500 HO
1979 Bayliner 2556 FB Convertible Cruiser
Heavy Equipment Repair & Specialty Welding...

GordonThree
Explorer
Explorer
Capacitor from eBay could be any old junk sealed in can and sold as a legitimate part.
2013 KZ Sportsmen Classic 200, 20 ft TT
2020 RAM 1500, 5.7 4x4, 8 speed

westend
Explorer
Explorer
....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?
'03 F-250 4x4 CC
'71 Starcraft Wanderstar -- The Cowboy/Hilton