On going Motor Start Up Issues

[Fotoman]

I'm having problems trying to start my Motor. I have a 1989 Ford 302 with a OMC outdrive. The motor fires up when I turn the ignition key to the start position and as soon as the key is in the run position the motor stops? Also, after a few start attempts I get a back fire thought the carb and it spits gas out the top of the carb. I made sure that all the plug wires were installed in correct position on the cap with the firing order of the 302. I have replaced the plugs,fuel filter, ignition switch, cap & rotor, and installed new plug wires. I checked all wiring on the motor and all the fuses. Everything seems to be OK. Dose any buddy have any ideas what the problem might be? This is driving me nuts.

 

[Boatin Bob]

Re: On going Motor Start Up Issues

Check voltage at the positive post of the coil with the key turned to run. The coil gets power from 2 different sources, while starting it gets a full 12v from the assist solenoid, once started and you turn the key from start to run then the power comes through the resistor wire to feed a reduced voltage to the coil, if the resistor wire is broke that could cause your problem.

 

[Maclin]

Re: On going Motor Start Up Issues

Sounds like it could be a ballast resistor circuit problem.

Measure voltage from the coil positive terminal to a suitable ground while the key is in the RUN position. If it is zero then that is likely the problem. The coil gets full 12volt power while the key is in the START position because the ballast resistor is bypassed. Once the key is returned to RUN the coil would get slightly less than 12volt power thru the ballast resistor circuit. If the ballast resistor or ballast resistor wire is broken then no power will get to the coil.

Trace the wires from the positive terminal on the coil, the ballast resistor or ballast resistance wire will be there somewhere. Look for breaks or melted insulation.

 

[Maclin]

Re: On going Motor Start Up Issues

Looks like Boatin' Bob has it covered as well, it takes me a long time to get my thoughts typed in.

 

[Boatin Bob]

Re: On going Motor Start Up Issues

Hey Maclin....at least we're consistent with the same story, maybe we're right???

 

[Maclin]

Re: On going Motor Start Up Issues

We will have to wait and see what Fotoman finds out, but until then I would like to think it is in the vein of "great minds think alike....."

 

[Fotoman]

Re: On going Motor Start Up Issues

Thank You for the info Boatin Bob. I'll check that out this weekend.
And Thank You Maclin, I'll let you both know how she checks out.
Any ideas about the back firing though the Carb and spitting fuel?

 

[Maclin]

Re: On going Motor Start Up Issues

That backfire thru the carb is normal when the coil has power when cranking but loses power when in RUN or ON. One cylinder essentially fires too soon when the spark cycle is interrupted and and catches whatever is in the manifold because the intake valve is still open. I am confident that it is a symptom and not a problem and will go away once the coil power problem is solved.

 

[Fotoman]

Re: On going Motor Start Up Issues

Thank you Maclin, that is good news. I thought it might be another problem.
I'll check out the coil power this weekend and let you know what I find out.
Have A Great Day!