Won't shut down

[AGENT 37]

My F100 is starting to do this..... it's running so well that it doesn't want to stop. I turn off the key and it keeps on running without a miss, I pull the kill switch and it continues to run. If I rev the motor up a little in neutral and drop the throttle back down it might shut off. I tried bumping the trim switch when it did it the other day and it shut down, today the trim switch didn't kill it. The "key on" power to my other instruments turns off with the key. I also have an erratic tach. The volt meter reads a constant 14 volts with the engine running though. I am suspecting a main power relay.... any other suggestions?

 

[mpsyamaha]

Re: Won't shut down

ive seen this problem a couple times before and it was the engine harness (goes from the dash to the big plug on the motor). right where the wires, hoses, etc go into the front of the cowl is often a spot that binds up and the wires inside get kinked when the motor is tilted all the way up. next time you run the boat and it keeps running when you turn the key off, go back there and wiggle and pull on that engine harness and see if it stops.

 

[AGENT 37]

Re: Won't shut down

I have with no luck. I also tried a different harness for the tach problem with no change (control box, cables, and 10 pin). Not saying that the continuous running and tach are the same problem...