LT 150 Surges and won't idle

[2032Ceta]

Just picked up a 2005 LT 150 that hasn't been used very much. In fact the guy I bought it from says he only used it one time a year for the last 6 years to bring mulch to his back yard. After seeing his yard, I can believe him...very small. Anyway, it looks almost brand new but it surges when at higher engine speeds and won't idle at low throttle. It has the 15 horse Kohler motor. I'm guessing a fuel issue as thing sat for much of it's life. He did buy it brand new and used for two seasons to mow a half acre, but then moved to this current house. He also through in the mathing john deere trailer that also looks brand new. My plan is as follows

Remove gas from tank
replace oil, filter, fuel filter, spark plug
Refill with 100% gas

Question, can I add sea foam to the tank to clean out the carb or is it better to pull the carb and clean it?
If you don't think it's a fuel issue, what might it be?

Any help is appreciated. Thanks.

 

[reynoldston]

Question, can I add sea foam to the tank to clean out the carb or is it better to pull the carb and clean it?
If you don't think it's a fuel issue, what might it be?

I don't see where sea foam is going to clean the inside of the carburetor. Pull the carburetor apart and clean it. When I clean a carburetor I like to let it sit overnight all apart in a can of carburetor cleaner.

 

[Rivets]

Follow reynoldston advice, but when putting it back together, install a new needle and seat.