attempting to run engine out of boat....no spark.

[generallee01]

Hey guys, needs some help with ignition stuff. I purchased a used motor and just want to test run it on a dolly prior to putting it in the boat. It's an 89' 4.3 Mercruiser with thunderbolt IV ignition. I'm a good wrench, but boats are new to me. I'm not positive about the distributor/ igntion wiring. MY Dist has 3 leads running into it in a harness...white/green, white/red, and black. there is also another black wire on the bottom of the distributor, which i believe is a ground. White/red and white/green run to the ignition module. Not sure if the black is a ground or not, or goes to - on the dist?! I jumped 12v to the + of the coil and have no spark. What goes on? I'm 100% sure I'm missing something.

 

[coastalcruiser]

Re: attempting to run engine out of boat....no spark.

look for the Service Manual #7 GM V6 1983 - 1993 (587 MB) in the adults only sticky at the top of this forum

 

[Don S]

Re: attempting to run engine out of boat....no spark.

While you do need to download the manual for all the information, here is the basic troubleshooting chart for the Thunderbolt IV ignition.

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