Our new to us LT 80 delveloped a problem today. At low throttle it stumbles and full throttle it stumbles. I pulled the carb apart cleaned out all the passages and jets, clutch feel fine and it pretty clean. I changed the air filter, transmission fluid with 10w40 and greased the zerk in back. Acts kinda like a vacuum leak or reed problem but I dunno. Ran great last time out. After a short run it will surge at idle n die. Any suggestions????

 

Found the problem n running well. I disconnected the oil injection while I was at it.

 

What turned out to be your issue? I'm having a similar problem

 

I had the needle/jet moving up and down with the slide on the carb. I ran the needle or jet as its called thru the top of the slide washer/throttle cable retainer instead of underneath it.