Check the throttle switch with an ohm meter or battery powered test light. At least on an 83 245 there are two switches inside. The center terminal is common to both. Connect between the center and one of the outside terminals and move the throttle. Does the switch change states? Then do the same with the other outside terminal. It should change state when the accel. is floored. Inbetween no gas and floored, the switch does nothing. On an 83, the switch is hard to get at. I came up from underneath. I had a similar power problem and found the rotor in the distributor had high resistance when checked with an ohn meter. It was a cheap rotor that had stainless steel under the carbon electrode from the cap and brass at the end delivering power to the four spark plug terminals. The joint between the stainless and brass was bad. jp