1989 Merc 150 starter/trim keeps dying...

[bsqared]

I've got a really nice 89 150hp that runs great, but has repeatedly gone dead after about an hour on the water- turn the key and not a sound. also the trim motor cuts out at the same time. replaced the starter solenoid and it was "fixed"- until the exact same thing happened next time out. I've replaced the solenoid a second and the "main motor" fuse- (that's what the local boat guy called it). it ran great again yesterday until an hour into the trip it started all over again. I can jump start the motor over the solenoid to get back home but the trim is still dead-


any ideas? I'm tired of fixing the same this over and over again.....

 

[GA_Boater]

Welcome aboard.

It's time to clean the battery cables on both ends until they are shiny and bright - These are going up to the motor and to the trim relays/solenoids. Also look at the cables for swelling and deteriorated insulation which is a sign the wire strands are corroding.

 

[bsqared]

yeah- I tried that, and replaced one battery that was getting old. Its baffling to me that it can be SO GOOD and then suddenly NOTHING from the starter. new starter, new solenoid (x2), all connections are good, batteries fully charged... and it does start up easily when you jump it at the solenoid.....(thank god for needle nose pliers)

confusing ?????????????

 

[Chris1956]

That motor will have a neutral safety switch in the MerControl. Try moving the throttle handle back and forth, while turning the key. That should "exercize" the neutral safety switch.

Of course, the trim pump would still work....