i recently overhauled an O360 and have run it. I noticed that the idle is fairly rough up to about 1500 RPM and it smooths out just fine.Suspecting a problem with the idle circuit, with the engine at idle I gave it a little shot of extra fuel with the primer and idle became smooth and then rough again which I take it to mean it is lean at idle. I can find no vacuum leaks and there is no play in the mixture shaft or the throttle shaft.
I started with the idle adjustment screw open 1 1/2 turns and opened it 1/2 turn between attempts until I reached 4 turns open and there was no change in the roughness. Anybody care to speculate on what else I can check? I hate to spend big bucks on an overhauled carb cause everything works fine above 1500 RPM including the accelerator pump. I am thinking of removing the idle screw and blowing some air into the idle orfice in case there some trash in there. I forgot to mention there is some exhaust popping an the idle range.
Comments appreciated.
John in Fl
I started with the idle adjustment screw open 1 1/2 turns and opened it 1/2 turn between attempts until I reached 4 turns open and there was no change in the roughness. Anybody care to speculate on what else I can check? I hate to spend big bucks on an overhauled carb cause everything works fine above 1500 RPM including the accelerator pump. I am thinking of removing the idle screw and blowing some air into the idle orfice in case there some trash in there. I forgot to mention there is some exhaust popping an the idle range.
Comments appreciated.
John in Fl