I recently resurrected my Falcon 56 model from the early 1970's. 1973 I think. I had to soak the engine in alcohol to dissolve all the old Castor oil. Even with all that soaking I needed to use my heat gun on the carburetor to loosen it up.

For fuel I've added Castor to a 5% nitro mix to get 20% lubrication. Some of that is synthetic oil of course.

The engine runs, starts easy but loads up at low throttle and after a short while at low throttle / idle, and it won't throttle up quickly without quiting.

Some observations... It runs better without using the pressure port on the muffler. (The muffler is a newer Enya muffler to meet the club noise standards. The original Semco flow through muffler didn't have a pressure port.) When it was on the pressure port it seemed to drip a lot of fuel off of the bottom of the engine. I assume that this is fuel coming out the front crankshaft sleeve bearing. The leakage is way down without the pressure port.

At this point I am thinking I should try a 10% or 15% nitro mix. Any thoughts about the use of synthetic oil on this engine? The glow plug is original equipment and the engine has not seen more than 3 or 4 gallons of fuel in its lifetime.

By the way that 30 year old Monocote is quite brittle. I'll have to re-cover it by the end of the season.

Any ideas???

Thanks
Mike