Gravely ZT48HD spits and sputters

[Todd J]

My dad has a ZT48HD with the 24 hp Kawasaki engine. It starts up with no problem but once up to speed it's starts to miss and will finally quit. It does this with or without blades engaged. It dies even quicker when blades are engaged (no surprise there).
I know it's not ignition problem because it's starts right up. Sounds like fuel problem to me. This model has the dual tanks with switchover valve. This valve is hard as hell to turn. Have to use pliers to do it. Does this sound like a problem getting fuel to the carb or more of a carb problem?

Thanks in advance for any and all help.
Todd

 

[mwshaw]

I had the same valve fail on my 148. The original valve stem was bad and has been replaced with a chrome one instead of pot metal. Dealer gave me a new one as mine was just a month out of warranty. It broke off and left me having to switch gas hoses between tanks to finish a job..