Axcel75

I have a 1991 5.0 Mercruiser, 230 Hp, with a 4BBL carb. It has a Thunderbolt Ignition IV. The engine ran fine for maybe 1 or 2 minutes and then died. I checked all the grounds and wiring and it all seems fine. I checked for spark and there was none. I then replaced the ignition sensor inside the distributor cap and the cap itself. I then tried the engine and still nothing. So I replaced the ignition coil. and still nothing. I'm wondering if it is the Ignition Module itself or something else? I was told that perhaps I put in the wrong ignition sensor and that could be causing the problem.

I'm at a loss and I could really use some advise.

Thank you so much,

James

JaayTeee

Did you check the shift interrupt
switch on the shifter cable bracket ?

This, if sticking, will ground the
neg. side of the coil.


Do you have a pos. voltage at the
pos. side of the coil ?


jt

220BR

Here is a trouble shooting guide for th TBIV. TB IV Troubleshoot

Axcel75

Thanx for the trouble shooting guide....I'll check all the components.

James