1990 25HP electrical puzzler

[Mr. Coffey]

Clean filtered fuel. Engine revving under load at approx 2-revs per second. Able to determine that upper cylinder was not sparking. Started with a new coil for each cylinder. No change. Then detemined that by swapping spark plug wires and power pack ignition wires to the other cylinder, the failure moved to the other cylinder. That pointed to the power pack. Installed new power pack with no improvement. Any ideas what's next? Thanks!

 

[Cofe]

Re: 1990 25HP electrical puzzler

That is a puzzler

I wonder if the new power pack is bad?

And another thought to check the coil insulators on mounting bolts.

 

[234rick]

Re: 1990 25HP electrical puzzler

That is a puzzler

I wonder if the new power pack is bad?

And another thought to check the coil insulators on mounting bolts.

Its probably a used power pack with the same problem as the first one.

 

[Mr. Coffey]

Re: 1990 25HP electrical puzzler

Thanks for the suggestion about the coil bolt insulators. I'll check that. Power pack is new - bought it from an Evinrude dealer.

 

[jimdd810]

Re: 1990 25HP electrical puzzler

also do a compression test

 

[Mr. Coffey]

Re: 1990 25HP electrical puzzler

At your suggestion, I checked the coil bolts and insulating washers. In this case, the coils have to be grounded to the block, evidently. I took out the washers, the coils are grounded now, and the problem is solved!

Thanks for your help.
PS. Did a compression test early on - checks out OK.