View Full Version : 88' Prostar ignition schematic PLEASE!

05-01-2007, 12:31 PM
Could someone tell me what wire go from the ignition to the wiring harness to the solenoid to the starter to the distributor etc. You get the picture. Boat won't start and believe me I've been through the posts and have tried all the suggestions, but I want to make sure I have everything wired correctly before I take it in. Have a new battery, ignition switch, solenoid, coil and EI. Thanks.

05-02-2007, 11:50 AM
this might help...


I've ended up replacing ALL the ignition related wiring 1) MC may have undersized it from the factory so...I've gone with 10 gauge from the battery, up to the ignition switch then back thru the neutral safety switch then to the solenoid. My boat starts EVERY time. I also went with one of these...


Once again, my boat starts EVERY time...I don't think the starter turns the flywheel 1/4 turn before it kicks...

I did mine piece-meal but knowing what I know now, I would have just re-wired and re-distributored it right from the beginning...too many headaches any other way...

Good luck...if I were you I'd not even fool with the wiring in the harness, just run in new...just my 2 cents

Did I tell you my boat starts EVERY time...

east tx skier
05-02-2007, 02:41 PM
This may or may not help, but I received this from a very reliable source for a late 80s Prostar.

05-02-2007, 02:55 PM
Here is what I have for a schematic. Its actually for a PCM 351w, but it should be pretty darn close. The things most likely to be diferent are:

-wire colors
-engine harness pin numbers
-I believe MC/Indmar utilized the 4th post of the solenoid (I) to send +12V to the positive side of the coil when cranking.

Also note that the actual physical connections arent necessarily made at the ground lug or ballast resistor- these connections are commonly made internal to the engine wiring harness.


05-02-2007, 03:56 PM
Dunno where you are in you quest for spark - did the boat run before you installed the EI? Is the neutral safety switch at fault?

Tell us the sequence of events leading up to the failure and someone here will be able to work thru it with you!

east tx skier
05-02-2007, 05:54 PM
Here is what I have for a schematic.

Wow, Tim, that's a lot prettier than mine! :)

05-02-2007, 09:54 PM
I bought from a guy that owned for 10+ years and I'm beginning to think he knew it was going to be a slow death. Anyway, the boat would start and run for the first month I owned it and then occasionally I'd have to reset the 50 amp breaker and THEN it would start. I don't live on the lake anymore and I got busy toward the end of the year and didn't get back up to the lake. My cover was old and leaked, so there was moisture everywhere when I went up to get it out. I went to start it and nothing. First thought battery, got a large charger/starter cart unit and let er charge a while and then tried. Nothing........so I bought a new battery.....nothing......so I was advised to buy a relay........when I went to try it the ignition stripped!!! Bought new ignition....nothing! Pulled it out and winterized it! This year I bought a new higher cranking battery, another relay (cheap), EI. Upon opening up the terminal I found some corrosion, so I cleaned all that up and tested. I took all the wires for the ballast resistor and put them together accordingly. I took the nuetral switch and tied them together. I took the safety switch and tied them together. I get 12V to the relay..through the nuetral switch up tp the ignition and back to the relay... I get the dash lights....then turn it to run and get the buzzer...but when I crank it I get nothing. I ran new wires to and from the ignition to the relay and tested. I went through all the grounds except pulling the starter off and cleaning the mounting surface. Our lead maint man at work used to be an auto mechanic and is very savvy, so I'm hoping with an extra set of hands and another brain I can figure this thing out. IT CAN"T BE THAT HARD! Can it???? lol

05-03-2007, 10:36 AM
One of my later experiences (before I rewired the entire system with 10 ga.) was to put a meter on the "S" terminal at the solenoid and had my buddy turn the key switch to "start"...meter read a paultry 6.xxx volts (that's when the light bulb came on for me suggesting that my wiring might not be exactly up to par - although it LOOKED OK...)

I assume you've used a large screwdriver across the large solenoid terminals assuring yourself the starter works???If not, rebuild starter?

It was explained to me that the "S" terminal wiring has to be PERFECT allowing current to flow....(one of my earlier attempts was just to replace the wire from the key switch back to the "S" terminal - this seemed to help some however the real joy came when I ran in new 10 ga. ALL THE WAY - she pops off like a fire cracker now - along with the DUI distributor that eliminates ballast resistors, coil, coil wire and allows a great big spark plug gap (.05)...my boat has been born again..halaluha! praise da lord!!!

I'd suspect the starter...your reference to having to reset the breaker leads me to believe it's EXTREMELY high current draw due to corrosion and other bad things within the starter????

05-03-2007, 09:22 PM
Thanks for the help. The boat is started and I'm on my way with the rest of the restotation....all over. It was the ground and a bad (new) relay. The terminal strip also needed cleaned up. Thanks all and I'll post before and afts when I'm done.