1995 350 Big Bear will start up and run for afew seconds but when you put in gear and accelerate it cuts out and wants to die. If you do get going with the choke about half on it will run OK for awhile and then act up. Have got it warmed up and seemed OK but acted up after running around the lot for a minute or two. Does not loose spark, the guy that worked on it before me replaced boot between the carb and cylinder and put new carb onto the unit with no change in performance. Have good fuel flow out of tank to carb. Have good fresh fuel. Checked air filter and replaced the sparkplug. Thought I was having a air leak but have not found any. Does anyone have any other suggestion or have had this problem? Oh, I also set the valve clearances.
Thanks, TORK

 

Got a rusty gas tank? Inline fuel filter? Air filter is on, and air box lid is on?
Sounds to me, like its got a dirty carb float bowl, and the crud is blocking the main jet now and then, Or the air filter is missing or the air box lid is off, and causeing a too lean condition. Thats why using the choke helps it out.
I really doubt its a spark problem, because theres no tps and the cdi wont be able to know where the throttle posion is. Its almost certainly a carb issue.
Check for air leaks, around the carb to motor tube, and check to see where the mixture screw is set at, it should be around 2 turns out from seated.

 

You can try spraying small amounts of starter fluid around the carb to find air leaks, if the revs go up then you have an air leak.