75 hp Chrysler won't start. Where do I start??

[danthern]

Hi guys..I have a 75 hp Chrysler Model # 758H3F. I thinks this translates to a 1983 model. Has a Prestolite ignition system. Was running earlier this year but fried a bunch of wires on the water (reason uncertain). Got another harness, hooked it up and it turns over great, but won't start. I'm getting fuel so I think the problem is in the ignition system. I get 12 volts at the battery terminal(red), the heat terminal(orange) and the generator terminal(purple). Nothing at the choke(green), start(yellow), tach(white) orignition (blue). All with the key in the on position. Also get 12 volts to the battery and generator terminals with key in off position. I see no spark at the plugs. Does this motor have points and if so, where are they? Under the flywheel? Any advice on which direction to go would be much appreciated.

 

[danthern]

Re: 75 hp Chrysler won't start. Where do I start??

Let me add....there are 2 wires on the harness that connect to nothing. I'm a bit color blind, but I think one is black and one is grey...don't know if that helps........

 

[eurolarva]

Re: 75 hp Chrysler won't start. Where do I start??

Probably black in purple on the key side. So when you push the key in the choke does not engage? You will only get 12 volts on the yellow wire with the key turned beyond run to the start position which must be working because you mentioned that the starter spins but no fire. There should be a ciruit breaker on the port side somewhere. Check that to see if it is working. I believe starter will spin even if this is popped.

 

[danthern]

Re: 75 hp Chrysler won't start. Where do I start??

Thanks for your response. The engine sounds different when the key is pushed in for the choke, but I'm not certain that it's engaging. I don't see the butterflies move or hear a click or anything. This boat also has a remote choke switch that isn't currently connected since I just changed the wiring harness. I'm familiar with the circuit breaker. If I leave the key pushed in for choke, it pops out....I'm baffled..??

 

[eurolarva]

Re: 75 hp Chrysler won't start. Where do I start??

I have read that prestolite ignitions can be a bear to troubleshoot. A bunch of things could be a problem here. Regulator/rectifier could be shot, Circuit breaker popped. Have you tested to see if you are getting spark? You might want to go here to find help THE MARINE DOCTOR . In his chrysler forum he has a thread on testing prestolite ignitions however it will require using a DVA.

 

[danthern]

Re: 75 hp Chrysler won't start. Where do I start??

Thank you, I'll check that out. I don't see a spark at the plugs. I am getting 12V to the regulator, however. The quest continues, I'll keep you posted. Thanks again.

 

[eurolarva]

Re: 75 hp Chrysler won't start. Where do I start??

If for some reason you accidently hooked up the battery leads backwards even for a second or two you could have smoked the regulator. Good news is the regulator is still availible bad news it is like $350 dollars. Because you have power going to the regulator your circuit breaker is working. If the regulator is shot you wont get power to the ignition system and this could be causing your lack of spark. I would find out from The Marine Doctor if there is an easy way to test that regulator with an ohm meter. My manual does not cover that type of regulator. Also DVA tester adaptors are availible on line for as little as $35.

 

[mark23ca]

Re: 75 hp Chrysler won't start. Where do I start??

this is what i'm doing with mine as the harness was vandilized...i run the blue wire right to the positive strap on the selinoid and jump the selinoid with screwdriver and i get fire...does yours have a distributer running off of a belt??if so thats where the points are..it may be what ever fried your wireing harness is the reason u dont have fire..check for burnt wires arround the fly wheel and things like that....if u have a olm meter check for continuity in wires from the motor to the switch...but when i get no fire its sometimes best to bypass the switch ..it won't hurt nothing if u are carefull...DO NOT jump the selinoid if there is any gas comeing out of the carb or if laying arround the motor....being on fire sucks worse then a bad boat motor