Ignition System Troubles

[Hookshurt]

Does anyone know anyone that has alot of knowledge about the 5.7L Vortec Marine Power ignition systems? I have switched, replaced, and checked everything I can think of including checking every wire in the harness. I also went through the diagnosis portions of the manual without any success. Just for reference, I have swapped ECM, replaced ignition coil, tested ignition control module, replaced system relays, checked fuses, replaced distributor, rotor, and cap. The motor will crank, it is getting plenty of fuel, but there is no spark at the ignition coil. Thanks.

[Rawleigh]

Bad ignition switch? I know on outboards they can cause problems, but don't know about inboards.

[In Memory Walter K]

You can crank yet no spark? Work backwards from the coil. Gotta be a broken wire/bad solenoid/short something that's stopping the power from coming through.

[kellysmall]

That happened to me once with my old gassers. I ended up having to adjust the gap on the new ignition module before it would work.

-Kel

[captbone]

I agree with the other.

Install the spark tester inbetween the coil and the distributor cap. This will tell you if the coil is firing.

If not make the opposite engines boat wire harness hook up to that engine and start it with the other key.

Those two things will tell you all you need to know.

Just my 2 cents.

[Hookshurt]

Good info guys! Thanks, it gives me some more ideas to work with. I'm afraid I'm about to have to go through the trouble of finding an acceptable harness replacement for these bastardized motors. At what point does it stop being a diving platform for the kids and a vessel to fish on???

[Terry Frank]

Towards the back of those engines is a switch with a red button on it. Might actually be a circuit breaker. They go bad. The ones on my engines had to be replaced when I bought the boat as there were intermittant starting problems. I kept the replacements working with liberal doses of CX.

[Hookshurt]

Terry, I think I identified the breaker you are talking about. Mine is located on a bracket with the slave solenoid, ignition coil, and ECM. It is a 50amp. If this is the same one, I tested it and it is good too, thanks for pointing out that it is there. For some reason it didn't even catch my attention, I thought it was a Christmas light or something. I will be swapping out the "new" ignition coil with the one on the stbd motor's, testing the pickup coil, then swapping out the harness. Hopefully, I won't have to go that far.

this may sound far more ignorant than the rest of my questions, but how do you adjust the gap on the ignition module?

[Hookshurt]

Valuable lesson learned. Just because it is new, it doesn't mean it works! The final straw I had to pull was to check the "new" ignition coil. Guess what? It was bad. Another new coil and she starts like a champ. Lot's of hours wasted good lesson learned. Thanks for the input. I feel alot more comfortable about the condition of the wiring harness now!