[jjhdds]

My 77 rude has been acting odd lateley,the tack was all over the board now its stuck at 1000 rpm,my motor will start but WILL NOT TURN OFF,I also get my hot horn to go off when the motor is running, but the hot horn will not go ON when the motor is running in the OFF position,any thoughts.Thanks

[tashasdaddy]

sounds like you have a short in the controller. if it is the original controller, and wiring harness, the insulation gets brittle and falls off. could be any where in the harness. could be broken kill switch wire (black/yellow ). the ignition is killing the accessories line but no the engine.

[ezeke]

Check and clean the connections at the red plug at the engine. Check the harness just inside and outside of the engine housing for broken/shorted wiring.

Then use an ohm meter to check for continuity on the individual wires.

The black and yellow wire that runs from the ignition switch to the power pack works by shorting the power pack when the key is turned to "off".

The Grey wire that runs from the engine's terminal block to the control and then to the tachometer provides the pulse to activate the tachometer.

Since the two wires are basically unrelated, you may have just lost your ground at the engine, so check the wiring at the engine by removing, cleaning and reconnecting each wire.

[ezeke]

Forgot to mention that you might want to disconnect the battery while you do all of that checking.