[pumpkin head]

Be grateful for any help from any experts out there:Engine: Mariner 75 ELPTO 1995 2 stroke, 3 cylinderI changed the stator since the engine would not start and traced the problem to an open circuit on the low charge coil. Engine ran great for 3 or 4 days......Now i have a problem.The no 1 cylnder is not firing (diagnosed by sequential removal of HT leads. It produces a healthy looking regular spark but the cylinder will not fire. I stripped the carb and cleaned and reassembled but still no improvement(it looked pretty clean). The trigger coil ohm tests looks fine as do the primary and secondary coils. If i am getting a spark could the pack be dodgy or it more likely a fuel problem? Is there an easy test for this?I dont have a peak voltage meter. How can i be sure if its electrical or fuel?Any help greatly appreciated! Thanks

[Elmer Fudge]

Do a compression test on all cylinders and post results.

[WillyBWright]

Connect an inductive pickup timing light and run it. If the light flashes, the sparkplug is sparking. You can check any cylinder this way. I'm with Elmer on this. I think your problem lies elsewhere.

[achris]

Did you swap a known good spark plug into that cylinder and try again? Plugs have been known to fail like this.Chris.........

[pumpkin head]

Thanks a million chaps. Problem solved. I checked the compression seemed ok(approx 100psi each cylinder). Started the engine on each single cylinder to verify no 1 bad, then swapped around the coils- Number 1 coil would not fire no 2 cylinder. No 2 coil fired no 1. Pretty conclusive. Thanks for all your help. A happy pumpkin head.......

[Keith Buchanan]

I have exactly the same problem at the moment but I was discounting the coil because of the healthy looking spark I am getting.