Yerf Dog

[Fred G Sanford]

ok here are the pics we discussed. While taking pics found some issues. The clutch pulley not coming out of the engine (rear most) has side to side play. Additionally the throttle linkeage has me confused, looks like a mess. Not sure why it isnt running directly to carb, instead it goes thru this maze of wire linkeage. Any thoughts or directions would be appreciated

 

[B man]

Ok whats you have there is a Max-torque 20 series CVT. it needs wear buttons,but they dont make them any more for that series driven unit.

you'll have to buy ethier the new Series driven. or buy the wear plugs for the new series and cut them to fit.

the karts a Yerf-dog model 3020. its a recalled model do to steering issues.

 

[B man]

Ok whats you have there is a Max-torque 20 series CVT. it needs wear buttons,but they dont make them any more for that series driven unit.

you'll have to buy ethier the new Series driven. or buy the wear plugs for the new series and cut them to fit.

the karts a Yerf-dog model 3020. its a recalled model do to steering issues.

 

[jamyers]

...The clutch pulley not coming out of the engine (rear most) has side to side play...

You'll want to limit that by adding washers somewhere along the shaft, but MAKE SURE the backsides of both pulleys are aligned with each other.
EDIT: Probably not, I'm thinking of the Comet 30-series which is different. Get more info from somebody who knows Max-Torque 20-series before taking my advice on that TQ/CVT.

..Additionally the throttle linkeage has me confused, looks like a mess. Not sure why it isnt running directly to carb, instead it goes thru this maze of wire linkeage...

That's because on every small engine like these, the throttle is connected to a governor assembly, which is going to want to limit the max rpm to 3600 rpm or so. Basically, the actual carb throttle is controlled by the governor, so that when you mash the pedal you're telling the governor to open the throttle - which it does until the engine rpms climb to the regulated max, when it'll back off (even though the pedal is still floored).
Good video on Tecumseh governors here.

Also, the key engine numbers you're going to want to write down are: "OHH55", and for extra detail add in the "6910E". You can do a google search with those and come up with all sorts of parts, videos, pics, etc. For example, I googled: "tecumseh ohh55 69101E", and the first hit is a "Parts Tree" site with an exploded view and all the part numbers, where I get the carb Tecumseh part number = 640025C. I take that number to ebay, and I get a whole list of carbs, carb rebuild kits, etc.

 

[B man]

You'll want to limit that by adding washers somewhere along the shaft, but MAKE SURE the backsides of both pulleys are aligned with each other.


That's because on every small engine like these, the throttle is connected to a governor assembly, which is going to want to limit the max rpm to 3600 rpm or so. Basically, the actual carb throttle is controlled by the governor, so that when you mash the pedal you're telling the governor to open the throttle - which it does until the engine rpms climb to the regulated max, when it'll back off (even though the pedal is still floored).
Good video on Tecumseh governors here.

Also, the key engine numbers you're going to want to write down are: "OHH55", and for extra detail add in the "6910E". You can do a google search with those and come up with all sorts of parts, videos, pics, etc. For example, I googled: "tecumseh ohh55 69101E", and the first hit is a "Parts Tree" site with an exploded view and all the part numbers, where I get the carb Tecumseh part number = 640025C. I take that number to ebay, and I get a whole list of carbs, carb rebuild kits, etc.

Also specify if its a Power Sport model.

 

[jamyers]

Ok whats you have there is a Max-torque 20 series CVT.

Good catch, B man! Got any directions as to how he should shape new wear buttons?

C Baker, ignore my comments about adding washers to the jackshaft until some more-knowledgable-types chime in - it looks like that driven unit needs the shaft space when it expands. I only know a little about Comet 30-series (assymetrical belts), and I'm not finding much info online about the Max-Torque 20 series (symmetrical belt). Did find this site with good info on them; http://www.reliablegokarts.com/transmission.htm#tc

the karts a Yerf-dog model 3020. its a recalled model do to steering issues.

c Baker, don't let that scare you off the kart, it's fixable (and might have been already done on yours). http://www.diygokarts.com/vb/showthread.php?t=9837

 

[B man]

Good catch, B man! Got any directions as to how he should shape new wear buttons?

C Baker, ignore my comments about adding washers to the jackshaft until some more-knowledgable-types chime in - it looks like that driven unit needs the shaft space when it expands. I only know a little about Comet 30-series (assymetrical belts), and I'm not finding much info online about the Max-Torque 20 series (symmetrical belt). Did find this site with good info on them; http://www.reliablegokarts.com/transmission.htm#tc



c Baker, don't let that scare you off the kart, it's fixable (and might have been already done on yours). http://www.diygokarts.com/vb/showthread.php?t=9837

Ive done it to mine. basicly you buy the new wear buttons. cut them in half(cause there double sided.) then take the correct side and sand it little by little till they fit snug.

 

[jamyers]

Ive done it to mine. basicly you buy the new wear buttons. cut them in half(cause there double sided.) then take the correct side and sand it little by little till they fit snug.

Hmm...when I got new buttons for my Comet 30, I couldn't find double-sided buttoms, they were all one-sided (wanders off to dig around...There they are, part # G00130, down at the bottom of this page, same part number they list for Comet 20-series symmetric belt...are these the same as you're talking about,

or do the Max-Torque units take a different one? Just curious, I'd heard somewhere that Max-Torque and Comet were interchangeable, which of course could well be wrong...

 

[B man]

there different. MXT 20 series has a sort of curved ramp. comets are all flat.

 

[C Baker]

Im gonna look at the wear buttons, had a nice development this weekend. Friend had a cart with a 6.5 hp tecumseh. Cart will not move though. It starts and sounds real strong. The carb is newer as well. I took carb off and put it on mine. Instant improvement. Cart was running real strong, 23 mph per gps. Still have the issue of it taking off on start up, without gas pedal depressed, but we are getting there.

 

[jamyers]

...Still have the issue of it taking off on start up, without gas pedal depressed, but we are getting there.

Generally that's due to either the idle speed being too high, or the belt is too tight (either wrong size or pulleys too far apart).

Glad you're making progress!