How to choose the best distributor option to replace the wrong one

Mike94551

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I recently bought a boat that has some issues. It has what I believe to be an original OMC outdrive which would make it an '87. The engine is a 5.7 chevy vortec engine. Mid 90's to the best of my knowledge. I don't think the distributor on it is a marine distributor.

The problem is the shift interrupt switch does not stumble the engine at all. I have tested continuity on the switch and seems to test good. This distributor has the coil built right into the cap. Totally baffled at this distributor and know nothing about it unfortunately. I am quite certain that this is not the type of distributor to work with the shift interrupt system. Should I be looking into a different type of distributor one preferrably with an external coil for starters? Any advice on what to do from here would be greatly appreciated.
 

Howard Sterndrive

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Re: How to choose the best distributor option to replace the wrong one

coil in cap is auto not marine as you suspect.
we just kinda went through this yesterday here: http://forums.iboats.com/showthread.php?t=473664
OMC used an electronic shift assist module (ESA) that "stumbles" the ignition to cause the engine to shudder (try to stall briefly) and allow the lower directional gears to disengage from the dog clutch when shifting to neutral (and the ESA also could do this going into gear, but that was less important).
Your 1988 4.3 would have had points ignition and your ESA module (if it is original and still there) is only compatible with points ignition systems.
If you end up going with Delco or other modern systems, you can modify the ESA system to work more like Mercruiser's "shift interrupt" system, or you can buy a new ESA from Rapair/CDI corp that will be compatible with most any 4.3 marine distributor you can find - points or electronic.. the CDI ESA is about $90 or so
Mercruiser style shift interrupt is a popular mod for OMC's but you lose the stumble into gear, as the Merc design only stumbles coming out of gear...which is fine.


should answer your questions - just look for the 8 cyl version
 

Mike94551

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Re: How to choose the best distributor option to replace the wrong one

So a Delco marine distributor is a good quality brand? And then I would need to replace the ESA with a unit from Rapair/CDI and then wire in a regular coil? I totally understand that it only needs to work coming out of gear. There is no resistance going into gear from neutral. A lot of parts but if this will get me shifting smoothly I would be very grateful. Am I reading everything right and understanding the way to go?

Thanks
 

Howard Sterndrive

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Re: How to choose the best distributor option to replace the wrong one

sounds like you have the picture, Mike...

Delco is good, and cost effective - I think you will need to do the mod to a Mercruiser style Interrupt system, in which case you'll no longer need the ESA module- you just wire the switch to cut coil + supply (or ground the neg, I forget which) - search the forums there are a few threads about doing that conversion to an OMC... Merc uses Delco, and you just basically copy Mercruiser's shift interrupt system
 

Mike94551

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Re: How to choose the best distributor option to replace the wrong one

Howard,

Whew thank you so much for the help. I feel like I have a direction to go now. And the mercruiser style mod makes so much more sense to me than the workings of the ESA module. Again thank you so much for the help!!!
 
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