I just purchased a 1978 ATC 90. It starts right up and idles just fine. When I accelerate or rev the engine in neutral the engine begins to run poorly. I have no Idea how to adjust the carburetor. Does anyone have any simple, useful instructions for a novice?
I did drain the fuel and rinsed the tank with new fuel. Also installed a new plug as well as added a couple of ounces of seafoam to the full fuel tank.
