1987 3.0GM OMC - stall shifting from neutral, missing ESA?

OptimusGlen

Recruit
Joined
Jul 3, 2023
Messages
1
Hello all, new guy here.

First, the stickied "MUST HAVE" post in the top of this forum has broken links. Specifically, the How to ask a question and the OMC Information links, though I think the others as well. So, I apologize if I don't word this properly or include specific information.


I've built car motors, transmissions, etc but I'm new to the marine world. A bit of a learning curve here, but I'm able to turn a wrench.

I have a 1987 Forrester Phantom 164 with a 3.0 GM 4-cyl and an OMC Cobra. It's new to me and generally very clean. I've had it out 3-4 times and the last two have had an issue where it wants to stall when shifting out of neutral into forward or reverse. No issues going into Neutral. If I go quick into gear and give it a little oomf, it'll stay running. But if I'm going very slowly through channels to avoid making a wake it will occasionally cut off.

My first step was doing research on my own, which lead me to looking at the ESA or shift assist module. Only problem, it seems as though someone has removed it?

I was hoping you guys or girls could take a look at my photos and let me know what you think. If it has been removed, I'd like to put a new one in there and wire it properly, but I'm not sure what to get or what else may be rigged up on this...

Another item to note, the throttle/shift lever can be stiff to move. Maybe this is related somehow?

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Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,653
What may have happened, is that someone removed the ESA module, and wired it like a Merc Alpha, so that when the shift cable flexes as you shift from FWD or REV into Neutral, it momentarily shorts the ignition to ground. That can work, as long as you shift quickly so that it doesn't stall the engine. The whole point of the ESA module was to not short out the ignition, but lower the idle speed low enough to allow the clutch dog to release whatever gear you're in. When set up properly the Cobra system will not stall the engine, you will see the RPM drop briefly on the tach when shifting from in-gear to neutral and when it goes into neutral it will come back up to normal (600 rpm, ESA lowers it to approx 450).
Why did they remove the module? Who knows, maybe it went bad, maybe they put in an electronic distributor that wouldn't work with the original OMC ESA module.
It would have been bolted to that bracket where the wires are hanging through.

Your problem is stalling when shifting into gear, correct? No stalling when shifting from FWD or REV to neutral?
Idle speed should be checked with the boat in the water, in fwd gear. Idle should be between 500-600 rpm. If you have stalling still, you may have some tune up related problems to sort out. Ignition & fuel.
 
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dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,322
So many granny shifted broken pinion gears. V8 models suffered the most from this
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,653
shift it quick for that satisfying THUNK not a grrr---crunch....
running the same lower gearset 20+ years....
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,653
Because the original (black) cable supplier changed specs & OMC was slow to train techs how to adjust them. Recall cable was red. As much as has been said it isn’t hard to do this you have to follow the steps & don’t take short cuts! As I said I figured this out myself in one afternoon. It’s not rocket science!
 
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