5.0 Merc I/O blowing main 20a fuse under helm

[dmoorejr]

2005 Larson 206 5.0 220hp blowing 20a main fuse under helm when accelerating. Had an extra 25a fuse so put that in. Started boat back up and accelerated again, didn't blow the fuse but engine cut out. Putted back to dock and installed another 20a fuse and proceeded to accelerate and popped fuse again. Shift to neutral and when revving motor in neutral also pops fuse. Using a 25 - 30a fuse it wont blow but the motor will turn off. Any help appreciated.

 

[Fun Times]

Hi there, welcome to iboats!

One thought would be to make sure that none of your control cables aren't rubbing on any of the power wires either at the control unit backside or anywhere along the way to the engine. Though least likely, the safety kill switch at the controller has two purple wires that go to the ignition system that may be rubbing.

Also try turning the key on with the engine off and move the throttle to see if it blows the fuse as well.

Maybe, http://www.boatersline.com/viewtopic.php?p=6940

Keep an eye on what your volts go up to. Best to use a multimeter for testing purposes.

 

[dmoorejr]

Doesn't blow when engine isn't running, also won't blow if you put a 25a in, but the motor will cut out if revved up or attempting to plane, seems when a 20a fuse is used it blows before the motor cuts out, but using a 25a the fuse holds but motor cuts out

 

[Bt Doctur]

And the voltmeter is reading?????????????????????????