1991 225 HP Ignition

[Whitey436]

Engine starts right up without fail.

When under power seems that cylinders 3 & 5 will drop out randomly.
The WOT will spin 5500 RPM but will drop to 50-5100 RPM.
At all speeds this will occur, slow at idle speed 1400 drops to 10-1100.

Totally random when and for how long it occurs.

The voltage on cylinders 3 & 5 drops out but I dont what is causing it.

I bought two new ignition coils for 3 & 5.

I bought a used CDI and swapped it myself. The engine does the EXACT same thing.

I check the Pulser coil, charging coil, ignition sensor all resistances read within acceptable ranges. My local mechanic cannot figure it out, and says although the resistances are in range that when the voltage is high things break down, of course he cant explain what is breaking down.

Any other ideas would be appreciated.

Thanks,
Keith

[jb123]

i had an issue like this with a 89 pro-v, it had leaking coil leads,the wires going to coils, which i simply shrink wrapped each

run at night to look for any errant spark

it could also be dirty carbs

[Whitey436]

Thanks for the reply!

I am assuming the coil to plug wires but just wanted to ask to be sure?

We changed the coils on the cylinders in question. I liked the idea of trying it at night.

Everyone has said possible carb issues, but the mechanic said he saw the coil voltage drop and then return so your idea is the most reasonable based on what I have tried and also feasible explanations. Maybe I shouldnt be weighing the mechanics info since he couldnt solve it.

In a perfect world, if I move the coils around, marking them first so I know who is who, the problem should follow the coils.

I will try it tonight as is and then if I do not see anything I can swap coils around.

The supply side voltage per cylinder originates from the CDI or from wires under the flywheel?

[jb123]

mine were the leads going TO coil