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ESA question with a difference

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gregwatsonau

New member
"Hi Again guy's. After fi

"Hi Again guy's. After finding a bent shift bellcrank on my transom unit. I realise I have to sort this stiff shifting problem. I have a 5.7 Ltr with a Cobra leg. The engine was originally 4.3 Ltr and has been replaced with a rebuilt Automotive Chevy. (I have no idea when)Suffice to say there is no ESA unit on the engine, not even any wiring. I still have the micro-switch unit on the boat but the wires are not connected. The Engine has a Mallory distributor with a coil built into the dizzy cap. It is unlike anything noted in the manual so I assume its automotive as well. My question is: does anyone have any ideas how I can rig up an ESA system on this unit. I guess I can find a wiring diagram for the coil system but what ESA unit do I use. (If I can get one here in Australia) Does anyone have an internal wiring?component diagram of the engine ESA unit. I might be able to make one."
 
Greg...I don't think OMC e

Greg...I don't think OMC ever published the internals of the ESA although today there a company called CDI/Rapair that makes aftermarket ESA's that are electronic ignition compatible. If you still have the interupt switch you try wiring it up like a Mercruiser. Basically one lead of the switch goes to ground and the other goes to the negative post of the coil. When you shift and the cable moves the arm for the switch it will ground out the coil. You need to shift quickly and decisively otherwise you can stall the engine. This approach would be easy and quick for you to implement to try.

ps...shouldn't have an auto distributor in a boat.
 
"Thanks Bob. I hear you about

"Thanks Bob. I hear you about the distributor. I've uploaded a pic of it. What do you think. It maybe marine, I'm not sure. I though someone may have had a diagram of one they made. Concidering the age I cant imagine them being too complex.


191618.jpg
Distributor"">
191619.jpg
Microswitch assy
 
"Sorry...can't help with t

"Sorry...can't help with that distributor. I see in the other pic you do have the interupt and overstroke switches there. I'm not sure how you would wire up to that coil, does it have a pos and neg posts inside?"
 
"Hi Bob,
I was wondering more

"Hi Bob,
I was wondering more so if you could tell if it was a marine distributor or not.
I think I will be able to work out the earth.
What your saying is that when the microswith is made negative terminal of the coil is grounded??
What about the overstroke micro. Does it do anything in the mercruiser setup."
 
"I've never seen one like

"I've never seen one like that, was hoping someone else might have recognized it. All the Mercruisers have is the interupt switch, they never had or needed the overstroke, that was strictly OMC to work with the ESA module and the later versions of the ESA no longer used the overstroke because put an internal timer inside the ESA.

Yes the microswitch grounds out he negative side of the coil, effectively killing the spark for the duration of the shift. If you shift too slow or the switch is not adjusted right you can potentially cause the engine to stall."
 
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