84 OMC 3.0L Ignition problem?

[jwscott]

I bought a boat cheap, Put a new transom seal in it and took it for a spin, it had a weird intermitant missfire.

So i did new dist cap and related parts, plugs looked good so I just cleaned/gapped them, adjusted base timing, and checked for automatic advance, it was working, checked all connections cleaned them if needed. and that didn't fix anyhting.

SO what is happening, the boat starts fine, idles fine sometimes (sometimes its missing a bit) goes into gear perfect and drives fine at mid throttle ranges, but ocassionally you can hear and feel a miss, like its dropping a cylinder and picking it back up especially when your at higher rpms. (when this happens the tach jumps around and if when a timing light is attached the light shuts off)

ocasionally when its doing its missfire thing the boat just completely dies from a fast run, comes to stop, but if I turn the key and it starts and is working fine again.

I don't have a ton of experience with distributor ignition systems. so I was wondering if maybe you guys could give me some ideas on where to start?

the coil faultly? I did run a wire to the + side of the coil when it was missing to see if maybe it was a bad resistor or something but that did not fix it.

thanks for any help!

 

[wire2]

Re: 84 OMC 3.0L Ignition problem?

Wait until dark, start it up and have a look at the ignition wiring, in particular, the coil HV tower. I expect you'll see some corona and/or arcing. Once a spark jumps to the 12v terminals a few times, it deposits a carbon track, and will keep doing it.

 

[jwscott]

Re: 84 OMC 3.0L Ignition problem?

I will do that come this weekend, I am currently 8 hours away from my boat so I would like to compile as many suggestions as possible to figure this out!

wire2: I see your from Milton, I'm from Mississauga actually.