1997 GTS Shutsdown at 1/2-3/4 speed

[wrenwick]

My unit will shut down at 1/2-3/4 speed. I would crank right back up. I tried turning gas valve to reserve and could run at full speed. I switch the gas lines on the gas valve putting the reserve line to the ON position and the regular ON line to the RES position. I still could not run full speed in the ON position but again I could run full in the RES position.
I replaced the gas valve this weekend but no improvement. I installed new plugs and now can run at 3/4 speed- the unit does not shut down now but the engine will still not run full speed.
Any Thoughts are greatly appreciated.

 

[Billa]

1996 gts

I have a simular problem. Replaced the main gas filter - no change.
I am getting new carb filters as the next step. But I don't understand how switching to reserve helps sometimes.