Clarence Lee’s Blog
Using mufflers during break-in
Clarence, Is it safe to use a muffler when breaking in a lapped piston engine? I have some nostalgia-legal K&B Greenheads and Johnsons (.15 to .32) that I plan to use in NOS free flight. A couple of them (the Johnsons) are still a little tight and may need additional running with castor-based fuel before mounting but [...]

ENYA’s 180X-GS Gas/Glow Engine– A closer look
“Engine Clinic” columnist Clarence Lee shares news about this intriguing new powerplant in his upcoming column; here’s a sneak peek! During and following WW II, I spent seven and a half years as an Army Air Corps/Force pilot. During this period I had the occasion to fly a variety of multi-engine aircraft. Many of the [...]
Accident with back-firing 4-stroke
Q: Greetings Mr. Lee, I am addressing this to you because I know that a lot of folks read your column, you are most knowledgeable on engines. Late last October I was starting a new 4 cycle, 1.50 engine for the first time. I had a high quality aluminum spinner attached with the standard adapter [...]
Fuel feed issues
Q: Clarence, thanks for this forum. When the magazine shows up, it is the first thing I look for to read. My question is this: If you have a fuel feed problem caused by a low tank position will remounting the remote needle valve to a lower position solve it, or is the tank position [...]
Throwing a prop
Q: I have started the Thunder Tiger 91 mounted in the plane and amhaving troubles. With three different plugs tried (Two F types and one Fox Miracle Plug) and three different brands of 15% 4 stoke fuels being used, the motor dies when glow driver is removed and motor likes to kick the prop loose [...]
Engine won’t run?
Q: I talked to a very nice lady at Air Age and she gave me your name and said, ” he can fix any engine and if he can’t Clarence Lee could give you the answer you are needing.” So here is the question, my new ASP .12 will start and run full throttle and [...]
Low tank position and fuel draw
Q: Clarence, thanks for this forum. When the magazine shows up, it is the first thing I look for to read. My question is this: If you have a fuel feed problem caused by a low tank position will remounting the remote needle valve to a lower position solve it, or is the tank position [...]
Engine Shutdown Procedure
Q: I have an O.S 81 FS & 110 FS with the closed crankcase–no external vent or nipple. What advice can you give me for shutting down after each flying session? It is not practical to remove the glo plug each day to load after run oil. The aluminum head & steel threads on the glo plug — [...]
