Starts right up but wont restart when warm

[bahaha]

1978 Mercrisier 140 HP Alpha One-

I just purchased the boat and as others have described it started right up and ran great for the test drive. It also started right up for me but after about 20 minutes (temp was about 140~150) it stalled when I shifted into reverse. I got it back to the driveway and the next morning it started right up again. On the next time out the exact thing happened and I checked the coil and starter on the hot side with a test light and the it was very dim but the battery and other hot connections were good. When I tried to start it, it cranked very slow even though the battery was fine. After about an hour the test light glowed bright again on the coil and the starter and it fired right up. Please dont tell me its a fuel problem unless you can explain in detail how the fuel caused a drop in amps to my coil even when I go from the battery directly to the coil. PS I just replaced the coil...

Thanks for your help!

 

[Don S]

Re: Starts right up but wont restart when warm

but the battery and other hot connections were good.

Check the grounds also, and all those battey cables have 2 ends. Corroded/loose cable ends on the cables make a battery cable worthless.
I see this quite often, people bring the boat in and tell me it won't start. and that they have changed batteries and cleaned the connections where the cable attaches to the battery. Not realizing they are using a junk cable.

 

[Bondo]

Re: Starts right up but wont restart when warm

Check the grounds also, and all those battey cables have 2 ends.

Ayuh,... So do All of the Grounding wires....

You've got either Bad wires, or Bad wiring Ends...

 

[diehard]

Re: Starts right up but wont restart when warm

check your timeing if it is to far advanced when it is hot will be hard to turn over ...a lot of time when a coil is going bad it will fail when it gets hot but work fine when cold ?

 

[P 0 P E Y E]

Re: Starts right up but wont restart when warm

Check your wire harness plug for corrosion.

Testing around the coil can give fluctuating readings depending upon if the points are open or closed.

The best time to troubleshoot this fail mode is when it is occurring