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Delco EST wiring

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wufibugs

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I got ahold of a Delco EST distributor/coil for my 1989 Wellcraft 170 with Mercruiser (GM) 3.0L 4cyl.
The distributor has two plugs. Left plug/harnes goes to the ignition coil. Right plug/harness has 4 wires. There is a special 3 wire harness for timing. On this harness wires 1 & 2 are jumped together; wire 3 is connected to 12v. The regular plug/harness has only 1 wire that goes to the shift interrupter.
What I need to know is which wire of the 4 wires goes to the shift interrupter. Is it the leftmost or rightmost. I've looked online at several wiring diagrams and it is unclear. Any help you can provide is appreciated.


Richard

PS: Tried to upload a .jpg picture of the distributor but it doesn't seem to have attached. Any idea why?
 
The info below should help get you headed in the right direction including the 2 links posted by Don'S in post numbers 2 and 4 of my last link to you below...Your wires from the switch ought to be White/Green not blue as described in the EST Instructions of pages 6 and 4 which covers some of the wiring colors.

https://marineengines4less.com/images/companies/1/EST Ignition Instructions - ME4L.pdf?1431462059320

http://www.boatfix.com/merc/Bullet/90/90_15.pdf

https://forums.iboats.com/forum/eng...distributor-on-3-0l-mercruiser-some-questions
 
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I finally figured it out. The issue was the 4 prong plug on the distributor. I made two harnesses. The first is for normal running: Wire nos 1 & 2 are not used. #3 goes to the shift interrupter. #4 is never used. Second harness is for engine timing: Wire nos 1 & 2 are jumped together, #3 is connected to a 12v source. Unlike the original points distributor, timing is set at 1 degree BTDC.
 
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