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[vpitcher07]

Hello everyone, I'm new here so some noob questions incoming.... Me and a few friends have decided to build a go kart after finding a 8 HP Tecumseh snowblower engine. The engine runs great, but I need some help on how/what I need to attach it (clutches etc..) As for the frame, we have found one on craigslist that we are going to look at but before we buy it we want to make sure this engine will even work. Here are a few pictures of the engine. If anyone could point me in the right direction as to what kind of clutch I need and if this engine will even work, that'd be great!!!

 

[souperman000]

I think you can just use a centrifugal clutch for the engine. Depending on the way the engine turns, the exhaust might point right at your seat. Can treally tell from the pics though.

Welcome to the forum!

 

[vpitcher07]

Ok great thanks for the reply! Does it matter what type of centrifugal clutch? Do they have specific HP ratings?

 

[souperman000]

I dont think so, but you need the correct gearing to avois burning up your clutch. Just make sure it is the correct size to fit your shaft

 

[anderkart]

We need to know the diameter of the outer-half, of your engines output shaft. (is it 3/4" or 1" maybe?)

We also need to know the length of just that outer half, where it has a keyway machined in.

 

[vpitcher07]

the diameter is 3/4 inch and the key is 1 2/3 inch long. This is a pretty rough measurement as I don't have a caliper on hand...

 

[anderkart]

Most 3/4" bore clutches are made to fit engines with 2-7/16" long output shafts.

Here's the only clutch I know of that works on short output shafts like yours: http://www.out2win.com/catalog/noram.html#arena (these come with a spacer you would not use)

As an option, a machine shop could turn your crank to a 2-7/16" usable length. They'd have to broach the keyway longer too. I've also heard of guys cutting the end off another crank and bolting it on to extend cranks like yours.

 

[vpitcher07]

Thanks for the reply! So pretty much my output shaft is too long? I'm going to remeasure with something better than a crappy old tape measure to make sure what I said was correct. What would happen if we used this length anyway? Not to mention, the frame we were going to buy on craigslist is no longer there... Back to the drawing board.

 

[anderkart]

No yours is too short.

Your output shaft is probably a normal overall length, but it would need to be machined down to 3/4" its whole length to fit standard go kart clutches.

Like this pic:

See most clutches really need a 2-7/16" long shaft to offer proper support.
A clutch like this would hang way out past the end if your shaft.

Your output shaft might be fine to mount a torque converter, I think they only slide on an inch or so.

That clutch I suggested above is designed to work on cranks like yours, but its a heavy duty race model so its very exspencive.

2 more options would be replacing your crank, or you do have enough length to instal a solid gear, and you could mount a lower cost clutch on a jackshaft like this pic:

 

[vpitcher07]

OK I think i Understand what you are saying. Here are some pics with the measurements just for clarification. So where it gets fatter is where it needs to be thinned out to 3/4inch and keyed?

 

[anderkart]

Yes

 

[r_chez_08]

I think you may get a clutch on that shaft, depending exactly on where the keyway is.

Maybe someone with a 3/4" clutch could measure to see how much keyway would be on the shaft. I would say 10mm would hold if you bolt up the clutch tight.

Do you have access to a lathe? If so, it wouldn't take long to machine it down. I would say that with little experience you could get that crank out, machined and back in again in half a day.

 

[vpitcher07]

Thanks for the responses! Unfortunately i don't have access to a lathe. As of right now, I'm also without a frame so if anyone knows a good spot to find a very cheap frame let me know! It looks like we could probably work something out to fit a clutch to this thing.