You can tighten up the throttle valve cable. It's the (usually) black cable that goes from the throttle linkage to the right side of the transmission. There is an outer adjuster up near the throttle linkage end of things, try tightening it (rotate counter clockwise as viewed from the cable) a couple turns. There is a more official way of adjusting it, but a couple turns won't hurt. OH and of course make sure it's connected, i have seen these become disconnected also.
Gilly

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