Just bought a late 80's early 90's LT 80. Unit started when I went to buy it, but was pouring rain so I didn't ride it. I get it home and have a heck of a time starting it. I figured its wet. Finally got it to turn over, but wouldn't idle very long. I performed a compression check and got about 140. I pulled the carb and cleaned it. It didn't appear dirty but i've never cleaned a carb before. I inspected the belt by removing the recoil cover. No dirt or debris at all. Couldnt see the clutch. The unit now starts and idles pretty easily and sounds good. But as soon as you hit the throttle it dies. My son did manage to get one lap around the yard and then it just wouldnt go again. One interesting note, I suspect it is fuel related because it will idle for about 10 minutes and then just die. I recrank it and it wouldn't start. If I turn the gas **** to prime, it fires right up. It still wouldnt drive but it does fire. I turn it back to ON and the cycle repeats itself. It appears the carb bowl is running dry? Does is still sound like a dirty carb? Any other types would be great. Thanks.

 

No. It sounds like a petcock issue. It's a vaccum operated petcock.
The hole on the carb closest to the motor is the vac port. A hose runs from there to the petcock. You can check to make sure the hoses are in the correct position.
Front hole (furthest from the motor) is the carb bowl vent.
I'll sum this up. Go to Advanced Auto or somewhere that they have a lawn mower section. Buy a simple on/off valve, a inline filter, and a 3/16 piece of hose.
Run the petcock in prime position.
Shut the valve off when done riding allowing it to idle for at least 30 seconds.
This will cure a ton of problems.
If you didn't remove both jets and clean them well, it would be wise to do so.