[seaturtel]

Motor runs great from the start. After running for an hour or more I turn it off. Then, when I try to restart the motor, sometimes starter keeps cranking with no result, and sometimes the cranking lasts for about 1 second with a switch in start, then cuts off. After about half an hour of
rest the motor starts again and runs great. The outboard is Johnson '77 140 HP. Have fresh water/fuel separator and fresh fuel and filter. Compression is good. Spark plugs are not fouled up. Any ideas would be greatly appreciated.

 

[Peashooter]

Sounds like the power pack is failing. Will not restart when hot. OK when it cools back down.

 

[OldDiver]

First I would try to bypass your start/off switches and the emergency shut-off if your motor has one. These can go bad and cause intermittent failures until they finally die.
Otherwise, if both cylinders are failing at the same time, it sounds like power pack overheating.

 

[seaturtel]

Thanks for the suggestions, guys. I will check it out. BTW, being a Solid State device, wouldn't power pack either be good or bad?

 

[pukahd]

Recheck all your grounds. I had the same exact problem. Changed over all the grounds on a single buss bar. Problem solved instantly

This post edited by pukahd 06/05/2008

 

[Peashooter]

Power packs can fail intermitantly due to heat. The tips about checking all your connections and especially the grounds are right on.
If you do this first and still have the problem then you likely have a problem with the power pack. Diagnosing outboard electrical systems generally requires special equipment and knowlege. When in doubt have a pro look at it. Replacing parts one at a time until you find the problem can get expensive.

 

[seaturtel]

Thanks for your input, Peashooter.
Perhaps you did not read my question: "being a Solid State device, wouldn't power pack either be good or bad?" Isn't your answer somewhat analogous to "being a little bit pregnant"?
BTW, the ground wiring and connection tips do make a lot of sense. Thanks.

 

[Peashooter]

A little bit pregnant.
LOL
I am no electrition but I know heat = resistance.
Power packs can experience intermitant failure.
Sorry but I can't explain exactly why.
Good luck!