4.3 no spark hot risers

[Estarnes67]

spent the last weekend on the lake with my 93 seaswirl 180 se with a gm 4.3 and omc cobra drive. everything was fine until the last run out. I was max WOT trimmed up going along just fine. As i started to bump the trim back down to come out of it, all of a sudden it felt like we hit a brick wall. boat just stopped doing about 35 mph. I turned it off immediately, it bogged for a second then died. opened the engine bay and didnt find a thing besides the risers were HOT HOT! turned the key on and the temp gauge was normal. boat wouldnt restart. got towed in and brought the boat home. found out i have no spark. got the test light out and have power going in and out of the coil. put the test light on the electronic ignition in side of the dist. and have a very dim light. almost not visual. same with the oil pressure sensor (not sure if thats correct with out it running with oil pressure?) put the cap back on the dist. and took the coil wire and a spark plug wire off the dist. cap. and tested with the test light. no spark coming out. spark plugs, wires, cap and rotor were new last year. also noticed the left breaker that holds the main wire harness was tripped. before i replace the ignition module in the dist. i kinda just wanted to see what everyone thinks? could the electronic ignition just go out like that at running speed? and maybe throw timing or something to where the exhaust would be hot like that? or does it sound like two separate issues? i removed the impeller and everything appeared normal, except the left port was still holding water, is that normal? dont believe i sucked anything up but its possible. any info or advice of where else to look would be great.

 

[southkogs]

Have you checked your gear lube for signs that you shredded your gears? I'm wondering if you might have locked up.

Does the engine turn over when you turn the key?

 

[Estarnes67]

The engine cranks over fine. No weird sounds. I haven't checked the gear lube. I know the omc's are known for losing gears. That was a thought in my mind as well. When I had the impeller cover off I had a friend looking at it and I just barely tapped the key and he said it turned. I just dont know if the impeller shaft is actually connected to the gear set?

 

[southkogs]

I'd check the gear lube. I don't know the Cobra well enough to tell you for sure, but I'd be thinking about disconnecting the drive from the engine. That way you can solve the engine start and run problem, and eliminate trouble in the drive.

Another idea to look for - and this is a total guess - look for a fusible link that might have been tripped during the "event."

 

[Lou C]

The engine cranks over fine. No weird sounds. I haven't checked the gear lube. I know the omc's are known for losing gears. That was a thought in my mind as well. When I had the impeller cover off I had a friend looking at it and I just barely tapped the key and he said it turned. I just dont know if the impeller shaft is actually connected to the gear set?

OK that is what's supposed to happen, the shaft that drives the impeller is on the end of the u joint shaft so it will spin anytime the engine turns.

About your lack of spark, I am not familiar with the electronic system on the newer OMCs, I have the old points and condenser set up. Check any of the wiring that passes around the elbows, if any wiring is resting on them, could it have gotten melted and grounded out? That breaker tripped for a reason, you have to find out why. See if you can find an engine wiring harness and trace the wiring from the coil to the distributor.
If your risers were hot but the engine did not overheat, you need to trouble shoot the raw water flow to the exhaust system. If the impeller is good, then check the thermostat housing for rust clogging the output ports for the exhaust manifolds.

 

[Estarnes67]

Update: Ok so I found an original ignition control module and coil on Ebay and ordered it. I put the ignition control module in and nothing changed. So I swapped the coil as well and still nothing changed. So I took the ground off the negative side of the coil and just barely bumped the key and it fired right up! I turned it off as quick as I could though because I didn't have any water hooked up. to be honest I really didn't think it was going to start. So I put the ground back on the negative side of the coil and no spark once again. I took all the grounds off the block and everything seemed okay no corrosion or anything. So what am I missing here? Is there a short somewhere else and when I hook the coil up it just shorts causing no spark? And then taking the ground off let's it fire up. I'm afraid to let the boat actually run for a while with the ground off the coil or is it fine?

 

[Estarnes67]

Am I even supposed to have that ground? The engine is already grounded but it appears that it was there from the factory

 

[Estarnes67]

Ok wow so I was completely wrong. I cut off all the electrical tape holding the wire loom and I traced it wrong. It actually runs up into my shift assist module