[NSRCA-discussion] Ideas?

[Ron Van Putte]

John Fuqua has been having an annoying and thoroughly confusing  
problem.  He has been using two different OS 1.40 RX engines for the  
past three years and they've run flawlessly until recently.  He's had  
one in an Impact since the early spring.  A month or so ago, the  
engine started dying in the air periodically when he advanced the  
throttle from idle.  He tried adjusting the idle mixture control and  
the main needle valve and the problem seems to go away.

Suddenly, a few days ago, the engine would die as soon as the ignitor  
was removed.  No problem:  it's the plug(s).  He's using the Mintor  
1.40 head on these engines and they have two plugs.  Replace both  
plugs.  Engine ran flawlessly for the rest of the flying session.   
The next day, the problem was back, exactly like it was the day  
before.  Then we removed the entire fuel system, cleaning everything  
and replacing the fuel tubing, fuel filter and tank clunk.  Replaced  
the glow plugs as well.  Engine ran flawlessly for the rest of the  
flying session.  The next day, the problem was back, exactly like it  
was the day before.   Yanked out that engine and installed its twin,  
fresh after a rebuild.  Engine ran flawlessly for the rest of the  
flying session.  The next day, the problem was back, exactly like it  
was the day before.  John has been using Morgan 20% heli fuel as long  
as he's been running these engines and it's worked great.   
Nevertheless, during this ongoing saga, we tried Morgan 30% heli fuel  
and Morgan Pro Power 20% and nothing seems to break the pattern.   
HELP!  We leave for the Nats tomorrow.

BTW, I have been using an OS 1.40 RX in my airplane for the past two  
seasons and have loved it.

Ron Van Putte