#77 wire gets hot

[kwb]

I pulled the spark plugs to crank the engine to hopefully get some oil moving before the start up. with the Ignition switch off and pushing the starter button the #77 wire got very hot at the tank. before I installed the wiring harness i did a continuity check on all wires and and i'm very sure they are where they should be. with the Ignition switch off and cranking the engine should the #77 wire have current ? could the oil pressure switch be the problem ? Thanks

[rickf]

The #77 wire is the fuel pump. It bypasses the oil pressure switch when cranking and runs direct from the starter switch to run the pump while cranking. I am guessing the pump is not running and that is why the wire heated up. What you can try is take the plug off of the pressure switch and put a jumper between the 77A and the 77 terminals and then turn the switch on and listen for the pump. If it does not run shut the switch off immediately! You probably have a either a short in the wire going into the pump or the pump is seized. Most likely a short since the pump is nothing more than a magnet and the current would be the same whether the pump rod was moving or not. Unfortunately you are going to have to pull the top off the tank and see what you have. But better now than out on the road. And technically if it were shorted the #77 circuit breaker should have popped but those breakers are so old they sometimes either pop for no reason or do not pop when there is a reason. With that said the circuit from the starter to the pump uses power from the starter circuit and does not go through the breaker so with the test I gave you hit the switch and listen for the pump and for a click behind the dash. This is where it would be good to have a test light on that plug at the same time.

[kwb]

Thanks rickf, I'll see what i can find

[kwb]

rickf, Thanks for your help with my fuel pump! turns out the pump was seized up. i had a nos spare pump but didn't think I would need it before it even hits the road. did my first start up today, put it on about nine hundred rpm for twenty min. and left it sit for five hours and did another twenty min. run. next time I'll adjust the valves hot I'll also put the timing light on it . I just set it according to the manual. It runs real good and no leaks. sure wish these old carburetors had a mechanical accelerator pump. got something going on when I start to push the gas pedal, starts to fall on it's face. on the last run I pulled the oil fill cap off and noticed it has quite a bit of vacuum . is that normal or do I have a breather system problem? Thanks. Ken

[rickf]

That means your PCV system is working but if it is a LOT of vacuum the valve could be clogged. You can take that valve apart and clean it just be sure to pay attention to the order things came apart and direction of the piston on there. The dropping on acceleration sounds like a bad accelerator pump or someone installed the spring on the wrong side of the diaphragm.

[rickf]

And if the pump is seized up it can be cleaned and reused as long as it is not an electrical short. If you are going to throw it out I would be happy to have you send it to me so I can give it a shot.