Any suggestions with the following, really annoying problem - I have a 240 carburettor model with a running fault. The first problem I experienced was a lack of power, the engine would only rev to 3000 rpm, and this would build gradually. This was coupled with the engine only running with the manual choke out at one particular position. After removing and inspecting the carb for something apparent, (I found nothing major) on refitting it was perfect..................for five minutes! then back to how it was. I've noticed two things since - applying the brakes affects the idle, it eventually stalls(?)and there seems to be excess fuel around where the air filter hose meets the carb.

Any suggestions to what this could be, would really be appreciated. Thanks