Forward Reverse work for a minute and then nothing...

[tadub19]

I am restoring a 74 HD DE and have pretty much replaced everything in the guts except the motor diodes and resistor coil. With that being said here lies the problem:

When I took it on it's first test ride it worked great! I got about a block down the street and then once I released the accelerator and then reapplied acceleration I got nothing. So I switched it to reverse and it worked great! I backed it all the way up to my driveway and released the accelerator and then reapplied acceleration and got nothing again! Here I sat at the bottom of my driveway unable to move forward or reverse.

Here's the kicker: The next day I went out to troubleshoot and the darn thing worked again! Low and behold when I drove it again it did the EXACT same thing to me.

If I let the car sit for a few hours it works and does the same thing.

Remember: NEW everything except diodes and resistor coil. I tested the diodes and they work correctly. I'm unsure as to whether or not the resistor coil even goes bad... I noticed that it does generate heat when the car was moving.

I retraced all wiring back to how the original guts were hooked up along with the wiring diagrams in the service manuals. Everything is correct and snug.

brand new batteries all tested good at 6.2-6.3V per battery.

I did upgrade the motor from the original 1.5HP to 3HP.

I have put a LOT of time and money into this gorgeous car and I am stuck. Please Help

[tadub19]

UPDATE:
I did replace the motor/charge diodes as well as the resistor coil. Did not change a thing. Still does not work properly.

Also, I changed out the key switch thinking the brand new switch I got for it ended up being defective... again, not the issue. I tried a different switch along with just clipping the wires together themselves to no avail!

I am about to have an aneurysm over this issue. If anyone has any idea what could be causing this I am open for them.

[Epb]

It reads like your resistor coils are getting too hot. They were made for the 1.5hp motor. Also make sure none are cracked.

[longld]

Tend to agree with Epb - something is getting hot and quitting - but must be a component that one is used for reverse and a similar one for forward - my suspicions lie in the solenoids since there is a separate one for rev and fwd. Could it be that the increased current draw of the motor (if it is) overheats the solenoid? If you temp short it does it now work?

[tadub19]

found out that it was a bad solenoid. when i bypassed the 6volt 4post solenoid the cart worked fine. So I replaced that new solenoid with the old rusty one and the cart works fine. I notified the merchant I purchased the solenoid from and I have returned the faulty one and they are sending out a new one.

I realize that I could just run with the old one but I am going for a full restore and everything looks new and shiny. If that makes sense. I've included photos

[Epb]

Very nice clean ride. Glad thats all it was.