Electrical problem on 90 hp Johnson

[Kiwifisher]

I have a very annoying problem on my 2001 90 hp Johnson v4 looper. Motor starts an runs fine when boat is on trailer with water connected to flush muffs. When I put the boat in the water, engine starts and runs fine but after a short while I notice the 4 warning lights flash as if doing a power on test and the audible alarm beeps. This may happen 2 -3 times. The engine still runs fine. Then suddenly the warning lights would flash in sequence again and the rev counter will stop working.

The engine will continue to run but trim/tilt won't work and if I turn the key off, the motor won't fire due to a blown fuse. Once I take the boat out the water and replace the fuse everything works fine until the next time I put her back in the water.

Has anybody got any ideas where to start looking for the electrical problem that's causing this? I'm getting desperate at the moment!

 

[Chris1956]

Re: Electrical problem on 90 hp Johnson

Start looking for melted wiring harness areas. Look where the boat harness plugs into the motor harness on the port side of the motor. Next check under the dashboard, where the harness connects to the gauges.

 

[Kiwifisher]

Re: Electrical problem on 90 hp Johnson

Thanks Chris,

After many hours of tracing wires, re-seating connectors, testing and trying to simulate the problem I've finally traced it to the Positive wire for the rev counter light bulb. The plug had come of the spade terminal and was dangling next to the steering box. Every time I'm on the water and start to accelerate thereby raising the bow, the wire would short on the steering box, blowing the fuse.

Small problem, very hard to find! Some days you just can't see the wood for the trees. Being a problem that only occurred when on the water, I was looking along the lines of water in the trim tilt wiring or wiring chafed through from raising/lowering motor or moving steering from side to side.

Glad it's sorted.