20 Amp Fuse Blows on Engine - The Hull Truth

shoemaker · 09-25-2008, 10:06 AM

A1, Thanks for the great feedback. My question is, my buddys HPDI 200 runs great for awhile, then when it gets 33 rpm or over he keeps blowing the 20 AMP Fuse, sometimes the engine will cut off and on a few times then the fuse blows on the engine, its the 20 amp that is to the right of the engine fuse box and lower one that says, Engine Control unit, Ing Coil, Electric Fuel Pump, Runs great till high speed, then the fuse goes and engine shuts down. Could it be the Engine Grounds on the block or do you think its the Electric Fuel Pump? We changed all the filters and the VST was very clean but changed it anyway and the tank was very clean as well, changed the filter on top of the VST tank as well as the Blub filter. We also swapped the ING key switch's and still had the same engine (stb engine) do the same thing, so we know its not the key switch. What do you think? Thanks for the great service.

A1 Outboard · 09-25-2008, 03:06 PM

It could be a number of things. I've seen ECU's that will intermittently blow the fuse, so the easiest way to check is to swap them. Of course the electric fuel pump can get warm and start to bind up causing a higher amperage draw. An ammeter inline with the B+ pump wire would show if the draw changes over time. Look over the coils carfefully for cracks or bulges and check the resistance of the primary and secondary windings.

Engine grounds should always be inspected and the mounting surfaces and terminals sanded until they shine. Do not reuse corroded lockwashers.

Inspect the wiring harness where it goes around corners and where it touches the engine. There may be rub marks, abrasion, or bare or shorted wiring.