3.0L fuse blows when starting

[F14CRAZY]

Hey guys, my OMC 3.0L was giving me some trouble on an otherwise excellent weekend...

We tied up and docked in St. Ignace for a couple hours. Went to start it back up and all electrical power was lost when I turned the key to "start". No gauges, radio, bilge blower...I checked the battery terminal connections and a few other things but found that one of the big 50 amp glass fuses on the startboard side of the engine was blown, the lower one. I've never had to check them before. The glass of the top fuse was broken but the link inside was ok.

The local auto parts stores didn't have a fuse in that size (AGU) but the Radio Shack had some. Thinking it was a fluke I went ahead and just replaced the fuse and tried starting again but it blew.

After running the situation through my head I traced the wires and decided to disconnect the yellow wire at the starter solenoid that goes to the starter. With the ignition on and using a screwdriver to short the big positive battery cable on the yellow terminal on the starter I was able to get it started fine.

Where should I begin troubleshooting this? Could the starter solenoid/relay go bad and cause the fuse to blow?

 

[SSSuper83]

Re: 3.0L fuse blows when starting

Where should I begin troubleshooting this? Could the starter solenoid/relay go bad and cause the fuse to blow?

Yessir! Check all your wiring around the starter and solenoid. Any corrosion will raise resistance like crazy, which will cause a blown fuse if its bad enough. Possibly the starter is worn also..but since it jumped off so easily with a screwdriver that really leads me to believe that its a wiring issue.

Just start at the starter and check EVERYTHING, including battery and cables.

 

[F14CRAZY]

Re: 3.0L fuse blows when starting

I thought I'd report back on my findings...

Today I took apart all the related wiring terminals on the starter relay, terminals on the wire from the keyswitch, wire from the relay to the starter, the terminals on the starter from the battery, etc etc...emery cloth, wire brush, and terminal cleaning spray. Cleaned off the pad that the relay mounts to as well. There's power being sent to the starter (a yellow wire) from the relay to the bendix solenoid on the starter (i think that's the proper term) when the key is turned but no activity from the starter (via multimeter). The relay clicks, fuses don't blow, and everything else on board is getting power. When I use the screwdriver trick I used between the "START" wire on the starter and the positive cables there it'll spark but no activity. I can jump the positive cables to the one terminal on the starter (bypassing the bendix solenoid) and the starter motor turns but doesn't engage the flywheel.

It seems my solenoid went bad at the same time...will be ordering a new one