Honestly, if you're going to spend any $$$ on that engine, you might want to reconsider....
Those Tecumseh 6.5 HP sport engines have a pretty short service life. I want to say they are only rated for 150 hrs. That's terrible if you ask me!!!
To get a new carb for mine (which I think it did need when I bought it) was going to be around $40 plus shipping.
That's when I found the Harbor Freight coupon for a Honda clone 6.5 HP engine for $100.
I installed that ($107 out the door) on the cart with only 1 issue. The new engine has a slightly shorter output shaft, so I made a spacer to take up the rest. Not a problem for you if you have access to a machine shop.
It's a 2 pulls to start motor, has a low oil shut off sensor, and has more power than the Tecumseh of equal rating. Not to mention every aftermarket option available for it if you ever decide you need to go faster.
As for the Comet 30 Torque A Vertor (TAV for short) how rusty are the pulleys if it sat outside? Mine was rusty/pitted a little bit, and it chewed up my new belt pretty good.
This will help explain how it works.
http://www.*****************/tavapp.htm
There is a bronze bushing that is on the smaller (driven pulley attached to engine) pulley that allows the belt to spin while in "neutral". If that bushing is frozen, I can see you smoking the belt in no time.
Is the correct belt on it? Ity should be a Comet 203591 for around $20
http://www.ebay.com/itm/GO-KART-DRIV...item27bd1f0a20
Hope this helps