There are several possible causes for a leaking carb. Most often it is caused by a blocked nozzle of the acceleration pump. If the carbs stay dry with the engine just idling, but become wet when you operate the throttle (and thus the acceleration pump), this is most likely the cause.

Take off the airfilter cover and take the airfilter out, so that you can look into the carb barrels.

If the engine has just run, there is enough fuel in the float chamber. It is not necessary to start the engine now. Look into the barrels one by one and operate the throttle by hand. The nozzles are in the top of the carb just behind the venturi's. They should squirt fuel into the barrel.

Each carb has one float chamber and one acceleration pump, which serves both nozzles (one per barrel). If one nozzle works and the other does not, most likely the nozzle is blocked. If both nozzles don't work, then they may be blocked both or the acceleration pump may be failing.

On the top of the carb there is a screw over each nozzle. If any nozzle is not working, remove that screw and use compressed air to blow any dirt out of the nozzle. If I don't have compressed air available, I use the hair of a steel brush (not recommended). Never use anything larger as you may damage the carefully callibrated opening in the nozzle.

Between the acceleration pump and each nozzle there is also a valve. If fuel still leaks from under the cover, best check these too. Take the cover off (carefully!!!). At the rear (towards the engine) you see two plugs. Remove those and check the O-rings. If necessary, replace the O-rings. Below the plugs are small rods, functioning as weights. Below the weights are small steel balls. Check that these are present. I have often found one of the parts to be missing.
- Huib -