89 mercruiser 3.0 EST igniton install

[vintage_snowmobiler]

I've done a little looking and didn't find what i was looking for, so my apologies if i missed something and make a duplicate. I have an 89 mercruiser 3.0 with the DDIS ignition. For the past several years i've had an issue with hesitation during a hole shot. Even if cruising and rapidly increase the throttle the engine hesitates. I've rebuilt the carb, bought a rebuilt carb, replaced plugs and wires numerous times, changed the pickup coil, set timing, everything, and the issue has stayed the same, did not get better or worse. I had the troubleshooting guide to the DDIS system and all checks are within specs. Finally i read that there are many issues with the system and parts are expensive, if even available and that it's better to convert to the EST ignition system. I have done that and have most installed. My only question is what side of the switch interrupt switch to i connect to. Since i'm not 100% sure how it works or what it does, i don't really know what side of the switch to connect it to. Thanks for any help that can be given.

 

[Fun Times]

Re: 89 mercruiser 3.0 EST igniton install

My only question is what side of the switch interrupt switch to i connect to. Since i'm not 100% sure how it works or what it does, i don't really know what side of the switch to connect it to. Thanks for any help that can be given.

What is the color of the wire you are hooking up to the shift plate?

I believe the answer you are looking for is on page 1C-44 of this link, http://www.boatfix.com/merc/Servmanl/6/6C1R3.PDF

I know Don has a highlight diagram floating around here somewhere with an arrow showing where to hook it up exactly, But I can't seem to find it at the moment. So I hope this works for you.

Good luck.

 

[vintage_snowmobiler]

Re: 89 mercruiser 3.0 EST igniton install

Thanks for the reply, It's been a couple weeks since i've looked at it, but there is only one wire coming off the distributor and it's black. I assumed it should go to the ground side of the switch, but i don't like to assume.

 

[fishrdan]

Re: 89 mercruiser 3.0 EST igniton install

I assumed it should go to the ground side of the switch, but i don't like to assume.

The EST ignition uses +12V for the shift interrupt switch, not ground like other ignitions (not sure what the DDIS uses), so you may need to rewire the shift interrupt switch. I don't have a diagram handy, but there might be one up in the stickies.

From memory, I think the shift interrupt switch needs to be wired in with the carb's choke wire, purple wire......