I have a new OS FS110a with pump that I ran my first tank of fuel through today. Using Wildcat 15% premium with 2oz of Benoil Castor/ gallon added I only am getting 7200rpms with a 14/10 zinger.
The other day I had to remove the cowl and engine and misplaced the needle valve. I ordered a new one it seems to fit correct The parts list calls for a "O.S. Needle #40D" and thats what I replaced it with
Based on what others are getting this seems very low. Im wondering could I have a pinched fuel line. Could I have the muffler screwed on to deep into the threaded shaft causing to much back pressure. Could the replacement needle valve be incorrect
Im just beginning to explore cause and would appreciate any input.
after two tanks of fuel Idles reliably at 1800. Needle valve at 2-3/8 turns out
For that size propeller, it sounds like you're getting the correct RPM. If you try a different-brand of prop, but the same size, you'll get different RPM readings. Try an APC, and you'll see quite a difference.