No Ignition 1993 4.3L Mercruiser

[98LSWON]

The engine is in a 1993 SeaRay. Its a 1993 4.3L Mercruiser w/ a Thunderbolt IV Ignition system. I'm getting no spark when I ground the wire from the coil to the distributor. I have 12V at the coil, the manual says replace the coil or the Ignition Control Module. That sounds too easy, does it sound right to you. BTW, What does a coil or ICM run? Thanks in advance for the replies.

 

[Don S]

Re: No Ignition 1993 4.3L Mercruiser

If you are following the OEM flow chart, replace the coil, if that doesn't cure the problem replace the module.
The coil is around $60 the module is somewhere in the 300 to 375 range depending on SN.

 

[98LSWON]

Re: No Ignition 1993 4.3L Mercruiser

I changed the coil. No luck. I removed the ICM, the plug was slightly corroded, would this cause it to die suddenly. I think it would make it start misfiring and sputtering, but I'm no expert.
Is there a way to clean inside the plug? I got the prongs w/ sandpaper. The ICM also had a white lubricant of some sort between it and the distributor. Is that normal? I hope this is the problem because i just ordered a $300 replacement.

 

[Don S]

Re: No Ignition 1993 4.3L Mercruiser

I removed the ICM, the plug was slightly corroded, would this cause it to die suddenly

Sure will.
You can replace the small wiring harness to the ICM. If the pins on the ICM look ok, just clean them up and install a new harness.

 

[98LSWON]

Re: No Ignition 1993 4.3L Mercruiser

Replaced the ICM and it fired right up. The wiring harness is still on the way and I'll replace that because of the corrosion on the connectors.

 

[achris]

Re: No Ignition 1993 4.3L Mercruiser

The white paste is heat-sink compound. Make sure you put some new compound on the back of the new module before you install it. If you don't the module will not be able to dissipate heat and will cook itself.

Chris..........

 

[98LSWON]

Re: No Ignition 1993 4.3L Mercruiser

The white paste is heat-sink compound. Make sure you put some new compound on the back of the new module before you install it. If you don't the module will not be able to dissipate heat and will cook itself.

Chris..........

I'm pretty sure thats what happened. The old stuff was dried out and crusty when I removed it.