Mr. Lee, I have been a long term reader and thank you so much for sharing your wealth of knowledge!      My question: I have installed a Thunder Tiger 91 4 stroke in a P-47 with the head at about 7 o’clock position. (Not quite totally inverted). So now the drain nipple on the bottom […]

Hi, I have a new  O.S. Surpass FS 120S III and the engine looks good in low idle but when I go to the air the engine become lean and the max revolutions are to low.  I tried any needle adjustment but the engine don’t have  enough power. Regards, Carlos V., Venezuela Dear Sr. V., […]

Clarence,     I have a OS BGX-1 mounted inverted in a one-fifth scale Pica P-40. I am using a J-Tec muffler.This engine is very hard to start. I usually have to turn the plane over, place in a cradle, then it starts, by hand, easily. I then shut it down, put the plane back on its […]

I tried Colman fuel on my Fuji BT-32B and my Zenoah G62 with C & H Electronic Ignition. Both engines ran fine with the Colman fuel and Evolution Synthetic oil mixed 35:1. I have on the BT-32B a relay kill switch that shorts the magneto and on the Zenoah G62 I have a electronic kill […]

I am a long time reader of your column, first time writer. I have learned a lot from your column, and I appreciate the service you provide with your engine wisdom.  I have been running four stroke model engines since my first OS FS 40 in about 1983. I have always “vented” the crankcase out […]

I want to replace the cam bearings in my OS 120 4-stroke engine.  I have replaced the crank shaft bearings but can’t get the cam bearings out.  Your help would be appreciated. Thanks, Greg Dear Greg, Unless it is absolutely necessary I would recommend leaving the cam bearings alone. If you do want to go […]

Here in the northeast, ethanol in the gasoline that we buy at the gas station is a fact of life. Clarence Lee has indicated that RC gas engines should be run on gasoline with no ethanol. In the recent past, ethanol was only blended into our gas seasonally, but now I think it is included […]

Hi :  I read your “engine clinic ” articles all the time and enjoy them.  My question is this.   I was given an O.S. .70  4 stroke “Ultimate:” as a gift.  I would never have bought a pumped engine but I’m stuck with this one.  I’ve been running 4 strokes for the past 20 years a […]