Go-Kart Engine Trouble

[J]

Equipment: Tecumseh OHH60-71106C in Murray Go-Kart. Two pedals: accelerator, brake. Manual start (must pull cord).

Problem: When try to start engine, Go-Kart wants to lurch forward. In essence, Go-Kart will not idle. Wants to start directly into run mode.

Description: Go-Kart 5 years old. Well maintained and in good condition. Rode well for 5 minutes yesterday. Cut off engine to take a break. When try to restart, go-kart lurches forward and will not start. It appeared to me that the engine was trying to start directly in run mode (not idling). I propped up the frame to get the rear wheels off the ground and tried starting engine again. Starts fine but wheels are moving at medium speed. Checked the accelerator and it is not stuck and appears to be operating fine. Tried carburetor adjustment ... no dice. Removed Torque Converter Clutch. It looks OK, but I'm not a mechanic. Torque Converter Belt also appears to be in very good condition.

Question 1: Started engine without Torque Converter Clutch attached. Noted that the engine shaft is turning upon start. Should that be happening? (My naive common sense tells me that idle means idle. When engine started and not depressing accelerator, then shaft should not turn?).

Question 2: Given description of the problem, anyone with small engine experience want to opine as to whether the difficulty is with the engine ... or with the Torque Converter?

Thanks for the assistance.

[Edwin Pawlowski]

Yes, the shaft is part of the crankshaft. Turn as one unit. Just like the blade on your lawnmower turns when the engine starts.

What you refer to as a Torque Converter is probably a centrifugal clutch. As engine shaft speed increases, the clutch engages. Ed

[Patch]

accelerator,

I think you have a clutch problem.

[Doug Miller]

That means the clutch is no good.

You misunderstand. The only difference between "run" and "idle", as far as the engine is concerned, is how fast it's running.

[snip]

Yep. That's the way they work. Just like your car. Ever look under the hood of your car with the engine running, and the transmission in park? Stuff's moving. That's what an idling engine looks like.

Nope. If the engine is running, the shaft is turning. "Idle" is simply the speed at which the engine runs when the accelerator is not depressed. Think about it: do you have to turn the key in your car when you want to pull away from a stoplight? No. The engine is already running, idling.

There's nothing the matter with the engine -- you pull the cord, it starts; you step on the gas, it speeds up; you let off the gas, it slows down. That's how it's supposed to work.

You don't have a torque converter, you have a centrifugal clutch -- which is supposed to engage only at high engine speed, not when the engine is idling. The clutch is stuck in the engaged position. Replace the clutch.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

[Chris Devidal]

accelerator,

J,

You're absolutely right about the fact that you have a Torque Converter. Most go karts either use a centrifugal/"throw-out" clutch, but some, like yours, use a Torque Converter, usually made by Comet. The engine shaft that you described should in fact be turning, because its simply attached to the crank shaft and when the engine is running, it will always be turning. "Neutral" as achieved when the belt is connected, but the main drum (that's connected to that crankshaft) is opened, and there is no pressure on the belt, so the drum spins, but the belt doesn't. When you hit the gas and the RPM's go up, the two halves of the drum begin to sandwich together, putting pressure on the belt, and making the go-kart move. As it gets up to speed, the drum continues compressing, until it hits the maximum diameter, giving the go-kart full speed.

So, in your case, the problem is that the drum is not separating at low RPM, putting friction on the belt and causing the wheels to want to move. It could be as simple as a lack of lubrication, or as serious as needing to replace the entire mechanism. There are a few different models, all with slightly different parts, so identifying which converter you have is your first step. Then figuring out what's working and not, and determining the need to fix/replace. A great place to start is

, with a good description of all parts, models, and terms in the glossary with good illustrations. I've worked with gokartsupply.com before, and they are some of the best around.

Hope this helps,

Chris Devidal [e-mail] remove SPAMBGONE to reply

[jim]

real simple problem. does the engine idle??? when the chain or belt from the clutch is removed or disconnected???? just go for the engine first... if it idles then your problem is farther up... like the clutch... the clutch might be grabbing before it it suppose to grab.. and this will make the wheels spin(liek when you had the rear wheels lifted... and yes the engine shaft should always turn when the motor is running... but at a slower speed(like Idle) and when you race it by giving it gas the clutch engages and then power goes to the wheels.... Or do you just have the Idle up to high????? this would make the engine race and then set the clutch into motion..... hope this helps.

[Randd01]

Those torque converter clutches always hang up not allowing the belt to be free. It is probably lack of lubrication between the cluctch cones and the shaft or a broken spring.

[Jim Yanik]

"Patch" wrote in news:1AUkb.4508$B_2.1500@okepread02:

Centrifugal clutch,when RPMs increase enough,pads lined with brake lining contact the outer hub and drive it.Either the pads are frozen in the out position,or the RPMs upon start are too high.

[Randd01]

I think he has a snowmobile type torque converter not a centrifigal clutch.

[J]

WOW. Thanks for all the Great Feedback.

1. It is a Torque Converter and not a Centrifugal Clutch.
2. When removed the Torque Converter Driver and started engine, I see that crankshaft is still turning. And RPMs move in relation to force on the accelerator. So problem must NOT be the engine.
3. I believe the problem is the Torque Converter Driver. It's stuck in engage mode and always driving the belt.
4. Going to pull the Torque Converter Driver apart and lubricate the weight assembly and hub.
5. The springs of the weight assembly are not broken.

But heck, I'm no mechanic. I wouldn't know if a Torque Converter Driver was broken unless it grabbed me by the ears and told me so.

If that doesn't work ... not sure where to look next.

accelerator,

[Karthead]

replying to J, Karthead wrote: I've got a 30 series torque converter on my prediter 212 on an golf cart and the slip ring keeps getting stuck in the converter might check that it's a little brass ring I pop it out put it back on and I'm good for another run but it gets stuck again