I bought one of these early this year and the first run was brilliant, after that it developed a hunting problem. Cleaned carby etc to no avail, today I mucked around with the idle air screw and the idle/pilot mixture screw. I set the idle air screw all the way in and then back out 1.5 turns (which is wrong, bad memory, the manual says back it out until throttle is closed and then screw in 1.5 turns). Mixture screw reset to all the way in and then back out 1.5 turns. It ran OK but still hunted a bit. Then I backed out the idle mixture screw another 1/4 turn (according to the manual this weakens the mixture) and it was perfect. Bit odd, because I thought it was leaning out before and my intent was to richen it. But I'm not complaining. If it runs well without hunting I'm happy.
Dunno where the idle air setting ended up but the idle/pilot mixture setting was the key for me. It makes sense, because when running on the governor and throttle being pulled back the engine would stop firing until RPM drops and governor allows more and more throttle to come in which would trigger the main jet and eventually bursts back into life. As soon as it is running fast the governor pulls throttle out until it's on the pilot system again. If your pilot system is not running well (too rich, too lean, or not enough air) you will always get hunting.
Last edited by Geoff-AU; 07/06/20 08:19 PM.
