Ok RCW - I checked with WD40 today for vacuum leaks, but no change in idling with that test. When I had the carb off last week I checked that the throttle & choke plate screws were secure, and that the plates had full movement. The control cables are free. Today I left the idle screw fully out i.e.: the throttle control tab was right up against its molded stop on the carb body. From a cold start the engine kept going but had to be nursed from very low idle rpm for the first minute or so. Thereafter the 'idle' speed slowly built up, through what I'd say was normal, to beyond 1000 rpm; blipping the throttle caused a further rise to a slightly higher plateau value. Suggests internal 'stickiness'? Certainly after 20 mins or so the idle is way too high at minimum carb setting, no-where near stalling. So I think I need to go inside the carb?
I also noticed that although the choke was needed to start, when fully warmed up and idling it appeared to have little effect if pulled on; no stalling as I used to see on car engines with manual chokes (many years ago!).
I will arrange a tacho over the next day or two and get some real rpm numbers. It's good to know about the torque converter fix in awkward cases; experience with these machines is so very useful. Thanks again.....
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