ENGINE WON’T IDLE

1 Idle fuel jet

The most common problem. The tiny idle passages get blocked with particles of dirt. Find the jet on the side of carburettor, two-thirds the way up. It may be housed in the screw plug, or behind it.

2 Clean the system

Clean the idle jet. If it was clean already, blow out the passages of the idle system through the fuel jet hole, mixture screw hole and the hole/passage where fuel-air mix is dispensed below the throttle.

3 External gremlins

If the engine idles badly, smell the exhaust. If it’s pungent and eye-watering, the float level is too high or it’s flooding. If it only smells slightly, the mixture’s weak – air leaks are the most likely culprit.