Throttle Sticking Full Open (Or so it seems...)

[Yttermayn]

I have a Columbia par car with a Harley carburetor, air filter, muffler, and throttle cable. It is a frankencart I built with my own three hands from the corpses of two old carts. It runs great, but if I drive around in it aggressively for a bit, the throttle seems to stick full open. I let off the gas pedal, no effect. I mash on the break and fight it to a stop. Turning the key to to off position does not kill the engine. If I turn the key to reverse, it struggles a little and finally dies. I immediately flip the cover up and check the position of the throttle lever on the carb, and it's all the way closed.
Anybody have a clue what's going on? I feel like it might have something to do with heat, but I am still learning about small engines. Also I must make note of the fact that it seems like I have to recharge the battery every other day, so I am wondering if there's some small draw even when the key is off? Maybe something engine related that is part of the above issue?
Thanks for your help.

[73eldo]

It does sound like maybe something is wired wrong. On the older carts the + power goes from battery junction at the solenoid to a fuse or circuit breaker. From there to the key. Key to the switch on the gas pedal. From the gas pedal it splits to 2 wires, one going to the solenoid and the other to the ignition coil. Foot off the gas or key off should kill power to the coil which should kill engine no matter where the throttle is. Killing the solenoid won't stop it from running, just stops charging and re starting.

Throttle is supposed to be sprung to go fully open if nothing is acting upon it. None of the cables are actually locked to the throttle level. The governor if its still there it can pull the throttle closed. The gas pedal also pulls the throttle closed.

[Yttermayn]

Thanks, I'll check that wiring. I think I found a service manual also, will pour over that when I get a chance. Thanks!

[Yttermayn]

Messed with it today. I thought the starter switch was sticking maybe. Took it out, lubed it with LPS1, flipped it over so it would wear in the other direction. Still sticky, though the engine always stops when I turn the key off. I may have had a sticky switch AND a sticky solenoid. I will look into that next.

[Yttermayn]

The plot thickens. First off, does anybody have a schematic for the reversing key switch for a Columbia par car/Harley Davidson gas cart? Mine has a diode in it and I can't find any reference to it in the service manual.
The problems I have been having: My cart used to have trouble shutting off, particularly in reverse. I believed the solenoid was sticking. Bought a new solenoid today and installed it. The cart works great in forward, but reverse just makes the solenoid chatter and the starter/generator barely does anything. I was hoping a schematic of the actual contacts and diode around the starting switch would illuminate things for me. What is that diode even there for?!

[flylear45]

The diode is for the reverse buzzer so it isn't buzzing in forward. Page 73 of the 1989 GSEL service manual has a key switch continuity test. If I was you I would start there to check that key switch is functioning properly. I'd also be testing the microswitch. Don't be confused with other info there because your cart won't be wired the same, but the switch test does apply.

The manuals link SHOULD BE IN A STICKY AT THE TOP OF THE FORUM but it isn't.

http://www.buggiesgonewild.com/columbia-parcars/


I don't understand when you say you flipped the starter switch. What did you do exactly?

[Yttermayn]

"Flipped the starter switch" - The Throttle microswitch, to be less confusing. The body of the switch is a rectangular box with spades on the ends and the button in the middle of one side; I flipped the orientation of the switch over aka rotated it 180 degrees along the axis defined by the direction of button travel. Kinda like for the same reason you rotate your tires. The button actually gets pushed in slightly off center, so I lubed the switch and rotated it 180 so that whatever parts inside will wear on newer, untouched surfaces, hopefully leading to more reliable operation.

[Yttermayn]

Yay! I figured it out! The previous owner wired the starter solenoid wrong. One side went to the throttle switch, but the other side was supposed to go to ground. Instead, he had it going to the F1 post on the starter/generator. Fixed that and it runs great!

[flylear45]

Originally Posted by Yttermayn

Yay! I figured it out! The previous owner wired the starter solenoid wrong. One side went to the throttle switch, but the other side was supposed to go to ground. Instead, he had it going to the F1 post on the starter/generator. Fixed that and it runs great!

Great! Good job and thanks for following up on the fix. It really helps to know what made it work.

[Yttermayn]

You bet! Thanks again for your help!