Suggestions on what to check... Now when I come to a halt, the bus keeps revving as if I've got foot on pedle. ????
OH yes... Sorry. I didn't touch anything in the end, just checked the valves and slight adjust. That sorted the idle. This is very over revving.
You could check the throttle linkage from pedal to carb to make sure it is free to open and return properly – including the fast idle cam on the carb.
If its a type 4 the little dampner thing on the throttle bar by the left hand carb unscrews and hold the throttle open on ours all of a sudden every 5000 miles or so
I have to switch it off at traffic light, reving like max. I checked the movement of pedal, cable seems fine, the throttle linkage returns strongly at carb when I move it with fingers. Underneath the front belly pan the accelerator cable feels very slack, is that right.? The only thing I've done is a new fuel pipe from pump, underneath to carb. I haven't ever messed with carb screws. What to do?
Check it's springing back right to the throttle stops because if the fast idle cam inside either choke is stuck that would prevent both carbs springing right back however strongly and smoothly it springs.
Another thing - I'm assuming these are Type-4 dual solex? The tiny nuts on the fast idle linkage between the choke and throttle lever can rattle loose and cause symptoms.
You may have an fraying throttle cable- hairy bits catching in the tube and holding the throttle open. It can also be spindle bearing wear allowing the throttle plates to move around and jam part open on the throat of the carburettor. When this wear happened on an old 34PICT-3 sometimes a quick stamp on the throttle and then it would drop back down.. Also a malfunctioning choke heater capsule can hold a throttle too much open with the engine warm. The throttle cable should just barely be going slack with your foot off the pedal (depending on choke cam operation it can be slacker cold than when its warmed up and the throttle returns to really closed) . If it is really loose that is a sign of jamming.
Mine does the same, at present I believe the accelerator cable is too tight or catching where it comes through the fan, resulting in the carb springs not being strong enough to close the throttles. This is on a Type 1. When accelerator cable is undone, all closes properly. Once I've finished with my current bodywork project, that's next to sort.
