Yamaha 90hp 4 stroke blow main 30amp fuse

Jwallk

Recruit
Joined
Sep 24, 2019
Messages
2
it keeps getting hot and blowing the main 30 amp fuse. Right before it happened I had a bad connection on the battery. I don’t see Any Burnt up wires or connections or any shorts. Where can I start trouble shooting? Could it be the rectifier? I Checked the battery it’s good. The fuse also controls the trim. The first time it happened I was idling and he just shut down and smelt like something got hot and burnt up
 

rejesterd

Petty Officer 2nd Class
Joined
Sep 20, 2018
Messages
142
I would get a peak voltage tester, and measure the peak voltage of the rectifier/regulator. The service manual will give you specs on peak voltage (typically it's 13V). If the rectifier tests fine, then I would start looking for a faulty connection somewhere between the control box and the starter. So that means the start switch, PTT switch, neutral switch, shut-off switch, the main wire harness connector at each end, main relay, PTT relay, starter relay, and starter motor. The peak voltage test is the easier one, so that's why I say do that first. But you might also find that you simply have a screwy PTT or starter relay that just needs to be replaced.
 
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