OMC vs Merc Interupter Switch conversion. OMC 4.3L 1989

[Stanp1]

Gents,

I've been weening my old OMC parts off and converting to Merc. I have a 1989 4.3L OMC setup. I want to ask if anyone has converted the OMC interupter switch and ESA to a Merc setup.

Here's why. I bought an SEI (alpha one) outdrive to replace the old cobra's I broke. It's my understanding, these models only need interupted coming out of gear and into neutral. I don't need the ESA and all the other OMC things that can go wrong.

What would your recommendation be for a Merc conversion, if one exisits? can I use the exisiting OMC cable bracket?

 

[bruceb58]

Re: OMC vs Merc Interupter Switch conversion. OMC 4.3L 1989

Here's why. I bought an SEI (alpha one) outdrive to replace the old cobra's I broke. It's my understanding, these models only need interupted coming out of gear and into neutral. I don't need the ESA and all the other OMC things that can go wrong.

The OMC also only needed to be interrupted going out of gear so no difference there. If the ESA is working, keep it. If not, you can rewire the switch so that it grounds the coil like a Merc does. You still need to use the existing bracket.

 

[Stanp1]

Re: OMC vs Merc Interupter Switch conversion. OMC 4.3L 1989

Bruce,

Thanks for the reply. I will leave it alone. Its been 3 years since I relaced the ESA module, so it's fairly new.

I can not achieve WOT with the current setup. When I get to 4400 RPM's, the engine boggs down like there is an over-rev switch or a miss-fire. Is this due to the ESA? I guess I could disconnect and try it.

Could it be the spings in the Distributor cap, not allowing the advance during high RPM's? Or does the Dwell need to be checked? I'm at a loss on this one.

 

[bruceb58]

Re: OMC vs Merc Interupter Switch conversion. OMC 4.3L 1989

Bruce,

Thanks for the reply. I will leave it alone. Its been 3 years since I relaced the ESA module, so it's fairly new.

I can not achieve WOT with the current setup. When I get to 4400 RPM's, the engine boggs down like there is an over-rev switch or a miss-fire. Is this due to the ESA? I guess I could disconnect and try it.

Could it be the spings in the Distributor cap, not allowing the advance during high RPM's? Or does the Dwell need to be checked? I'm at a loss on this one.

There are many things that could cause this from fuel filters to carb issues but the ESA won't be one of them.

As far as the dwell and the timing, you should be changing your points and checking these as part of a normal preventive maintnenance. Do a tune up and change your fuel filter and then see if you still have a problem .

Get an advance timing light to check your total advance.