I cleaned my grandson's Grizzly 80 carb (Mikuni VM16SH according to manual) over the weekend and now it idles only with choke or applying throttle. Adjusting the idle screw does no good. I think I am getting an air leak because when I blow propane on the top of the carb rpms go up. Even with choke the rpm go up and down. I am preparing to replace the top gasket, but also wondering about any o-rings I may have missed or lost. I completely dismantled the carb and saw no o-ring on the pilot screw (washer was there) or the idle adjustment screw. there is one large o-ring on the carb throat, but I'm not sure if there is on on the manifold. I have found one diagram that seems to show an o-ring for the idle screw, but only a washer for the pilot screw. Can anyone set me straight on the o-rings? Also, any ideas on the idle issue other than a possible air leak at the top gasket.

 

Wish this question had been answered because I came across this in a search after having the same issue tonight.

 

apparently no one si going to respond. I am going to check the carb again paying special attention to the slide. If I can't get it to operate correctly I'm going to buy a replacement carb from Zoom Zoom Parts. About $80. Anyone had any experience with them?