I recently purchased a trainer type plane with a converted engine at a swap meet. Upon taking my new pride and joy home I immediately went to fire up the engine. It sputtered and sputtered than it came life. Needless to say I was pleased! The engine however did not transition smoothly (it probably had not been fired up recently either!) but I thought I would run a little fuel thru it when BANG!!!!!! the magneto came off the engine housing and smacked into the prop. It did not look like a repair was possible because the mag was attached to the actual engine housing itself not bolted......
Just by chance I had to go to the local small engine repair shop to pick up my ailing weedwacker so I thought I would take along the engine for a "second opinion". The owner of the shop was amazed that weedwacker type engines were flying about the skies.... he immediately told me that my engine could not be repaired BUT he knew that this engine was a "Featherlight" engine and he had one in the junk pile on a weedwacker that had a problem with the long shaft..... but the engine was fine. Without encouragement he began to take apart the weedwacker, "wacking" off useless weight, and installing the machined stuff off my broken engine onto this "new" engine. Long story short, within 30 minutes I had an exact replacement.... I told him that I had questions about the Walbro carb with respect to high/low settings. This Walbro only has one screw adjustment on the top.... he thought that it was for the high setting.

Upon returning home I installed this "new" engine on the plane (EXACT fit..... all the mounting bolts lined up just fine!) I took the plane outside and it fired up on the first hit of the starter! I was back in business! Now here is my question...... The RPM's of this engine are 3200 low and 5990 high, swinging a Masterscrew 15x9 prop. I think the low is not low enough, and the high is not high enough. Turning the lone adjustment screw smoothed out the transition a little, but not much. There are not numbers on this Walbro carb that I can see.... I would send along a picture of the carb but I cannot find my docking station for my camera to get pictures into the computer.
Any suggestions??
Thanks!