1990 Mariner 25HP Blowing In-Line Fuse When Raising Throttle

Hello,

New to this forum....searched online and here but didn't see to much.

I have a 1990 Mariner outboard, 25HP. All last season I resulted to using pull start because of blowing the in-line fuse for starting. This year I wanted to fix it. I checked for all shorts in the lines but couldn't find any. I resorted to believing I am only blowing the fuse when using 50%+ of throttle.

Curious to ideas on what would cause this! I can't keep buying fuses every week so I may go back to just pull starting but I'd like to have have electric start since the boat is equipped for it.

I will include photos once I get back out to her tomorrow. Thank you in advance!

Are you saying the motor isn't charging the battery since a fuse in the charging circuit blows? Or is it a fuse in the starter circuit? (Never seen that before since that pretty high amperage.)

Jeff

fastjeff said:

Are you saying the motor isn't charging the battery since a fuse in the charging circuit blows? Or is it a fuse in the starter circuit? (Never seen that before since that pretty high amperage.)

Jeff

Click to expand...

The fuse is in the starter circuit. It blows and I cannot get the motor to turn over with the key anymore till I replace the fuse. Start up and kill, start up and kill, start up and kill and be fine but as soon as I head out and I believe it's when I reach a higher RPM, it'll blow.

Bad rectifier sending too much juice down the wire causing the fuse to blow?

The power generated increases along with the rpms on rectifier systems so I would put a voltage meter lead just ahead of the fuse and see what's coming down the line as you increase the rpms.

That's the "guess" that immediately comes to mind and at least where I would start troubleshooting.