Originally Posted by Flypast111

I am a “u-control line” model enthusiast and an owner of two (2) PAW TBR diesel engines, 0.19 & 0.40. I have successfully broken-in, or run-in, the 19 TBR, but I am having some difficulty with the 40 TBR engine. I have successfully run the following engine RUN-IN operations without using an electric starter;

19 TBR Engine:
a. ten (10) 2-oz. tanks of self-made diesel fuel through the 19 TBR without any major issue's
b. self-made diesel fuel formula: 30% John Deere ether starting fluid (part number RE556468; 80% ether & 20% alcohol), 30% castor/synthetic oil mix, 35% kerosene, 5% cetane boost … seems to work well … OK
c. followed supplied RUN-IN procedure and got good results … yeeaaahhh! … congratulations to PAW!

40 TBR Engine:
d. not so with the 40 TBR engine => in two different days of 3-5 hour duration events, I have only run about five (5) 2-oz. tanks through the 40 TBR engine … I also ran about two (2) short duration … maybe half-oz. … diesel fuel “start-slow run-stop” events as well … no other successful runs
e. in addition, however, I have experienced several low-cyclic motoring/firing resonance “back-&-forth” operation events ... which demonstrates that the engine is attempting to run, but will not “fully operate” per normal high-speed operation …. hhmmmnnnn!
f. also for note: the 40 TBR needle and venturi became “loose” during the initial RUN-IN and had to be tightened … the needle does not always demonstrate “stable” position control during engine firing …. sometimes it rotates +/- 30 degrees during operation … I removed the needle and “squeezed” the split-brass mount to reduce this behavior … it has helped ... but still the needle is not always fully “position-stable” … ???

Does any of this experience indicate to anyone just what is occurring here? Please advise further … I could use some help here to get this non-RC 40 TBR running “up-to” normal operations ... THANKS - Flypast111