BF90 starter or electrical problem.

[Marsol]

This is driving me crazy. I have a 2002 90hp four stroke. It doesn't get run very much. When I try to start it I get nothing at all. I've tried and done a lot of things but here's the oddest symptom I have. If I pull the starter out and touch the case to ground and touch the cable that is normally hooked to the starter to the other terminal (bypassing the solenoid) it engages and works. When I bolt the starter back in and bypass the solenoid with the same cable I get nothing. Not even a spark at the contact point. It's like the battery is completely dead, but it isn't. I've tested the starter on a bench by connecting power and applying 12v to what I assume is the solenoid terminal and it engages and spins powerfully.

I've checked the continuity between the ground cable and a bolt on the starter and there is a path there.

Any suggestions would be appreciated.

Mark

 

[JB]

Re: BF90 starter or electrical problem.

Ahoy, Mark.

Welcome to iboats.

A continuity check in a very high current circuit can't be done accurately with a common ohmmeter. The reason is that it only takes a fraction of one ohm resistance in a cable or a connection to prevent the starter from working. There is no ohmmeter that can see that.

Take all of the big, high current cables loose (both ends) and shine the connections before reconnecting.

I am not sure I understand exactly what you did, but that is the most common cause of a fully charged battery not being able to operate the starter.

Let us know how it works.

Good luck.

 

[BaileysBoat]

Re: BF90 starter or electrical problem.

Agree, clean battery cables. Suspect the main ground to the block is the culprit. Loose or corroded. High cranking amps opens the circuit.