switching to electronic ignition


Old 09-05-08, 06:20 AM
Thread Starter
Join Date: Sep 2008
Location: Midwest
Posts: 2
Thumbs down switching to electronic ignition

I have a 1989 Four Winns with a 3.0 Mercruiser, my advance mechanism is shot. Instead of replacing the distributor with the same, how hard would it be to convert it to the Thunderbolt ignition.. from the schematics it looks simple as long as I have the parts, but that shifter switch, what exactly does that do. Any help would be appreciated
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Old 09-05-08, 11:02 PM
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
Are you talking about the switch that kills the engine during shifting? It's a levered microswitch that shuts off the ignition as you come out of neutral just before the transmission engages. It lowers the torque so the transmission doesn't have to slam into gear. It's activated by a cam on the shift lever where the control's shift cable meets the shift cable that goes to the drive.
Old 09-06-08, 11:43 AM
Thread Starter
Join Date: Sep 2008
Location: Midwest
Posts: 2
Unhappy not sure..

I was looking at the schematics in the shop manual and it didn't seem like they used the switch on the mechanical distributor schematic, it looks as if there is a different device involved in the electronic ignition. Basically, my question if there are any issues in changing over to the thunderbolt ignition system from mechanical.

The module, distributor hookup wiring seems easy enough, it's just on the schematic there's a white/green wire coming from the distributor to a 'terminal block' where as no such thing exists in the breaker point schematic.
Old 09-08-08, 05:10 PM
Join Date: Jul 2008
Location: Montgomery MN
Posts: 541
It would still need the shift interupter switch I think the white green goes through the interupter. As rick stated it actually shuts power off to the ignition when shifting to "unload" the pressure off the drive gears. So if you run your power wire through the switch you should be able to do it. Have you tried a dealer for a new or used one? I live in the north wear we replace a couple blocks a year and a new block comes with a new dist. so the old one gets thrown out or put on a shelf. You might find one cheap.

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