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1990 318 won't turn over with ignition plugged in

Posted: Mon May 29, 2017 8:30 am
by honestcharlie56
Ok, so I got my engines back in the boat about a month ago. When testing running them on the bench I noticed they wouldn't turn over unless the ignition was unplugged from the coil. Thought it was no big deal, maybe they need to be plugged into the boat. Fast forward, they are in the boat and now same thing. I can jump hot to the solenoid S terminal and they will turn over, but only if the purple ignition wire is unplugged. Once the engine is cranking I can plug it back in and she continues to crank and shortly fires and runs fine. Both engines do this, swapped solenoids and resistors....resistors both get fairly hot while running. Any ideas?

Re: 1990 318 won't turn over with ignition plugged in

Posted: Tue May 30, 2017 5:02 am
by Fastjeff
I believe that purple wire should be on the "I" terminal?

Jeff

Re: 1990 318 won't turn over with ignition plugged in

Posted: Tue May 30, 2017 8:23 am
by barkleydave
Purple wire should be the I terminal (ignition) Cranking voltage should never run through the Purple wire. If it tries it cannot handle the load and I am surprised it did not burn the wire up if it did.

Check your wiring to the starter relay sounds like it may be mis wired. Mind you I am only taking a wild guess... !
Keep us posted on your progress.

safe harbors,

dave

Re: 1990 318 won't turn over with ignition plugged in

Posted: Tue May 30, 2017 6:14 pm
by honestcharlie56
Right, so with the purple attached to the I terminal I get no cranking at all (the solenoid does have a very very faint click to it though). Once I unplug the purple wire she will start to crank and as I plug it back in she will fire and run fine. Yellow with red tracer is connected to S terminal and purple is connected to I.

Re: 1990 318 won't turn over with ignition plugged in

Posted: Wed May 31, 2017 10:52 am
by EWRice
Sounds like a voltage drop to or at the ignition switch. Check it with a volt meter.

Re: 1990 318 won't turn over with ignition plugged in

Posted: Fri Jun 02, 2017 6:57 am
by Fastjeff
Had a similar problem on Mr Port for years. Cured it by installing a relay to trip the starter solenoid, taking 12 volts right off the nearby battery cable. These "Bosch type" relays are available dirt cheap on eBay, and usually come with a convenient base that has wires coming out of it. Use them for all kinds of tasks

Jeff

Re: 1990 318 won't turn over with ignition plugged in

Posted: Fri Jun 02, 2017 1:03 pm
by honestcharlie56
Ya I know I should have had my meter....my fluke bag (and all my fluke instruments) were not in my truck. I'll do some digging and report back, hopefully someone will find this useful in the future.

Re: 1990 318 won't turn over with ignition plugged in

Posted: Sat Jun 03, 2017 7:36 am
by barkleydave
I had a similar problem but found out it was a corroded fuse socket. Cleaned it up and all was fine.

dave

Re: 1990 318 won't turn over with ignition plugged in

Posted: Sun Jun 11, 2017 6:53 am
by honestcharlie56
Ok, thanks for weighing in gentlemen, it is always much appreciated. After toying with the voltmeter, switches, wiring, blah blah....dad finally says, "Just go buy two new solenoids and see if that fixes it....they're like 20 bucks". So sure enough, two brand new solenoids did the trick and the boat starts and runs great.

Re: 1990 318 won't turn over with ignition plugged in

Posted: Sun Jun 11, 2017 9:47 pm
by tundrarules
Crazy! Good find! Ole Dad saves the day! :mrgreen: