won't stay running

[Smiley2]

Mercruiser 3.0 litre 140 horse won't stay running, starts only stays running when I hold the key on. Reset the amp, checked fuel, spark, etc. any suggestions? I know there is kill switch, direct wired from ign switch to starter and same thing. Anyone have wiring diagrams from the gauges/instrument panel to starter? I think I have to trace the wires and see if grounding out somewhere.

 

[Don S]

Re: won't stay running

What year?<br /><br />Assuming you have a 1972 or newer engine, check for power at the + side of the coil with the ignition switch on. You should show around 8 to 10 volts. If not, you need to find out where you lost power at. There is a resistor wire on the coil going to the harness to lower the voltage that will go bad and needs replaced with a resistor wire kit to prevent point and coil damage.

 

[Smiley2]

Re: won't stay running

1987 Mercruiser Alpha One generation 1<br />Has new points, condenser, plugs, coil, starter, carb, only will run if hold the ignition key on.

 

[Don S]

Re: won't stay running

Did you check for voltage at the coil?

 

[Aquadzac Captain]

Re: won't stay running

I agree there must be some wiring problem to keep it running in a switch position. Bad switch or wiring issue. Get a wiring diagram to ensure correctness.

 

[95eclipse]

Re: won't stay running

I had this prob on my 95 Wellcraft. Turned out to be the kill switch that your safety lanyard connects to. When you crank the engine you bypass this switch is why it will run cranked. As soon as you return to normal position it dies. I bypassed the switch by jumping it out. Of course now it won't kill the engine if it's tripped, but I never connect the lanyard to myself anyway. If you have a warning buzzer on your boat you will hear it while you crank. If you don't hear that, your switch is not making connection. That's how I figured mine out. Good luck.

 

[Smiley2]

Re: won't stay running

How do you bypass the kill switch?<br />We have voltage from coil, infact it has new coil, starter, alternator, plugs, points, dist cap.

 

[Boatin Bob]

Re: won't stay running

I could be wrong but I didn't think the safety lanyard switch would let the engine start or run, I know it will turn over but it grounds out the coil whether the key is in start or on position. I think you need to take Don's advice and check for voltage at the coil with the key in the ON position, maybe you forgot to hook up the resistor wire when you changed the coil?

 

[Don S]

Re: won't stay running

If you have voltage to the positive side of the coil with the key in the run position, then it's not the kill switch also check that you have 12V to other purple wires on the engine as well. The choke and the alternator are 2 places you can easily find a purple wire to check. My guess is you have a defective resistor wire in your wiring harness.<br />But you have to check it to find out.<br />There is a resistor wire kit to repair the problem, it's Mercruiser PN 84-94227A 2