Problem: Tecumseh OHH60 in Go-Kart

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  #1  
Old 10-20-03, 05:58 AM
cellshort
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Problem: Tecumseh OHH60 in Go-Kart

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 diectly 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 carburator adjustment ... no dice. Removed Torque Convertor Clutch. It looks OK, but I'm not a mechanic. Torque Convertor Belt also appears to be in very good condition.

Question 1: Started engine without Torque Convertor 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 difficultly is with the engine ... or with the Torque Convertor?

Thanks for the assistance.
 
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  #2  
Old 10-20-03, 10:22 AM
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I am not a go cart expert, but I think the problem has to do with the engine. not the cart or the converter. There are two good reasons for an engine to start up in the fast running mode. 1st. The gas pedal may not be stuck, but the throtle may be stuck where it attaches to the engine or carb. On your engine whichever way the idle position is, make sure that the trottle goes all the way to that point. 2nd. The other thing that could cause this is your idle screw. Turn your idle screw counter clockwise, and the engine should idle down. If none of this works for you than you may need to talk to a gocart expert. I am not sure if Cheese is or not. Do these things above while you wait for Cheese to reply to your message.
 
  #3  
Old 10-20-03, 10:36 AM
cellshort
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Tried throttle and idle screw

Thanks, but tried both.

I did check the throttle. Hit with plenty of WD-40 and moved it around. Seems OK. And, while I had the wheels jacked up off the ground, I had my son step on the accelerator and back off. The throttle worked fine. The engine reved up and then back down. But it just won't idle. With foot off the accelerator, those tires are still spinning around at a good clip.

Also turned that idle screw all the way in, and all the way out, and every position in-between. (I called this carburator adjustment in my post ... guess meant idle screw).

I'm not a mechanic so this could be something common that I just don't know ... but this problem has me greatly intrigued.
 
  #4  
Old 10-20-03, 11:33 AM
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I would guess it's your clutch. When the engine reaches a certain speed, it engages to transfer momentum to the wheels. If it is engaged at low idle, there is something wrong. If the engine idles fine without it, then I would suspect it. Yes, the engine shaft should be turning. No pro here, but isnt the shaft part of the crank?
 
  #5  
Old 10-20-03, 11:55 AM
cellshort
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Shaft - crank - rod

Shaft - crank - rod

I'm no mechanic. In this small 6 hp engine .... I think they're all one in the same. In a simple man's mind - It's the iron bar poking out of the engine that moves even more rapidly when you step on the gas. I'm just not sure if the darn thing is supposed to be turning after the engine starts. Then, only when you step on the gas and cause it to run at an even faster RPM does the darn thing finally kick in somehow and move the wheels.

OK, let's assume it does turn at a set RPM when the engine starts. Then, as you step on the accelerator the RPM increases. At some point you reach a RPM high enough where the Torque Converter Clutch kicks in, grabs the Torque Converter Belt and turns it. The higher the RPM, the faster the belt turns. This action turns the axle which moves the wheels. Sounds logical.

So, if the go-kart wheels want to move when I start the engine, the Torque Converter Clutch is immediately reaching out to grab and rotate the Torque Converter Belt?

I've taken this Torque Converter Cluth apart and looked it over:

Drive Disc
Bushing
Torque Converter Inside Housing
Weight Assembly
Hub
Torque Converter Outside Housing
Washer
Bolt

Although I'm not a mechanic ... just don't see anything wrong. It's a $24 part. Wonder if it's worth the risk to just replace the darn thing and see if that solves the problem?
 
  #6  
Old 10-20-03, 12:33 PM
cellshort
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Driver, Torque Converter - Ouch

OUCH ! I was wrong. If it is the Torque Converter Clutch .. the part that I think might be causing the problem costs $100 (Murray Part Number 680167 ... Driver, Torque Converter). Not so simple to lay out $100 to change out this part and hope it fixes the problem. It's a sad state of affairs, but $100 is a bunch of money to me.

Before I go out and buy a $100 part - Anyone out there know how to identify a damaged Torque Converter Clutch?

Thanks.
 
  #7  
Old 10-20-03, 01:32 PM
cellshort
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Lightbulb I'm talking to myself

Finally found a good website with trouble shooting tips on my issue:

http://www.gokartsupply.com/trouble.htm

I'm down at:

DRIVE SYSTEMS
Torque Converter Equipped
Kart Moves While Engine Is Idling

1 Drive belt installed wrong (30 Series only, flat side of belt should be towards the engine)
2 Wrong drive belt installed (a belt that is too short will cause the machine to "creep" at idle)
3 Malfunctioning driver pulley (on crankshaft)
4 Malfunctioning driven pulley (on jackshaft)
5 Incorrect driver pulley spacing
6 Engine idle set too high
7 Pulleys not aligned (will also destroy belts)


Since it's run fine up to this point and the belt is in good shape - looks like it's either #3 or #4.

Anyone out there know how to distinguish between Driver Pulley Problems and Driven Pulley Problems ?
 
  #8  
Old 10-20-03, 06:44 PM
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It sounds like your belt transmission is sticking or engaging too soon. Look at Comet Kart Sales ( www.cometkartsales.com ). They are a racing go kart supplier and carry several of the clutches/transmissions that you are looking for.
 
  #9  
Old 10-20-03, 10:50 PM
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Hello Cellshort!

First of all, is the engine running at idle speed? Idle means low throttle...not running fast, just idling like no-one is hitting the gas.

The crankshaft does turn at all rpms, even idle. It turns when you try to start it.

If the engine is running at the low RPM of idle, and it is still moving, then the converter clutch is sticking. It could be either the drive or driven part. To tell which one it is, look at both. The bevelled side of each should be moved as far away from the belt as it can, making the belt ride at the lowest possible point in the pulley. In other words, the belt should be fairly loose at idle, and with the engine off. If it isn't, then one of the pulleys is not releasing the belt.

If the engine is not running at low idle speed, then there is an engine problem. It could be a throttle valve has come loose in the carb or something wrong with the throttle cable. Did the idle speed screw adjustments make the engine speed up or slow down? If not...then there is your problem. I'll wait for you to answer these questions before going into further detail.
 
  #10  
Old 10-21-03, 05:45 AM
cellshort
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Thanks Cheese

The go-Kart is at a lake house an hour's drive away. So won't be tooling on it again until this weekend.

Am thinking it's not the engine. Adjusting the idle speed did impact the speed of the engine, but did not stop the wheels from turning at idle. Will take a closer look at the clutch as it runs. It's probably the clutch (Torque Converter).

What would make a drive or driven torque converter not release a belt?

What are that chances of fixing the torque converter vs. replacing it?

Will post again next week to let you know what I find out.


Thanks for the help.
 
  #11  
Old 10-21-03, 03:42 PM
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I've had one on a golf cart stick when the shaft bushing in the moving half of the pulley wore out. There are also some plastic "buttons" that ride on ramps to move the pulley that wear. It also could just be dirty, but most likely something is worn out. Most yard karts don't have the highest quality parts so I would not be surprised if it is just worn.
 
  #12  
Old 10-21-03, 08:59 PM
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Agreed...wear and/or dry, dirty parts would cause it to stick. There's a pretty good chance of fixing it instead of replacing it. Replacement parts are available, so you could replace the bad part(s) rather than all of it. Remove the belt and crank up the engine. Look at the width of the pulley at idle speed. Then watch the pulley as you rev it up. The width of the pulley should get narrow as the engine speeds up, and widen again when it gets back to idle. If so, the drive clutch is working.
 
  #13  
Old 10-21-03, 09:16 PM
Tcumcman
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OHH60 Kart Engine

Cellshort,

When you mentioned you "turned idle screw in every position"...
what screw did you turn? One on the very top that touches the
carb throttle plate, OR....the one on the side just to right of the
welch plug ? The ONLY idle adjustment on that engine is the
top screw on the carburetor that literally TOUCHES the throttle
shaft when you turn it in. IN....MORE IDLE SPEED.....OUT....LESS.
The screw on the side is a "pre-metered, pre-set" screw that is
NOT TO BE MESSED WITH. Turn it all the way in, and leave it
that way. That sets the idle mixture and is there so that it can
be removed to CLEAN the idle circuit when necessary. From ALL
the comments thus far, sure sounds like clutch is trying to engage
TOO SOON at start-up. It should engage around 2200 RPM and
the idle RPM for the engine should be around 1800.

Tcumcman
 
  #14  
Old 10-22-03, 06:22 AM
cellshort
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Tcumcman

I'm fairly sure I was adjusting the proper idle screw. As I turned the screw in and out the idle speed was increasing and decreasing. Just was never successful in getting the wheels to stop moving while engine was in idle. So concluded that adjustment to the idle speed wouldn't solve the problem.

Now that I've recevied some excellent feedback for many helpful people on this board, I'm looking forward to getting back up there to see if I can find the problem.

Am fairly confident that the problem can be solved by lubricating the Torque Converter Driver. If not, am wondering, could it be possible that there is something wrong with the engine that makes it want to run at higher than normal RPM and thereby causes the Torque Converter Driver to always be engaged?


Thanks to all.
 
  #15  
Old 10-22-03, 02:32 PM
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That is very possible. The engine needs to run at a low idle or the clutch will not release. If the belt is loose when the engine is off, but tightens when you crank up the engine, then it is running too fast.
 
  #16  
Old 10-22-03, 06:51 PM
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I have been watching these posts for a while now and I just got a idea. Most likely it is because of the converter clutch, but I thought that if this engine is not new, than mabie a carb cleaning could fix this. It could be that the engine is not really idling although you think it is but I guess it might be possible that if a carb got dirty it could do the oppisette of not running and run to fast. What do you think cheese? Could this be possible. If cheese says it could, than go ahead and clean your carb really well. I am talken about using gumout spray and a soft clean tiny brush to clean that thing.
 
  #17  
Old 10-23-03, 10:05 AM
cellshort
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Terminator

If I don't get a fix by cleaning and oiling the Torque Converter Driver and Driven pulleys, I'll give the carb cleaning a try.

Thanks.
 
  #18  
Old 08-28-09, 07:25 PM
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Location: Akron, OH
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I googled this engine model for some carb help with the float, but i found this, i dont know if this is old or new, but for reference to anyone who needs it, i have a go cart with the same engine, the problem for me was the throttle adjustment on top of the carb, theres a screw that you can turn to set the throttle start placement, heres a pic:

just turn the screw so the throttle start position is back a little then the original placement, dont make it to short or long or the throttle will be messed up, just adjust it so it doesnt move at start up, now this MIGHT fix the prob fully, or it might fix it PARTIALLY, it worked for me.
 
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