Originally Posted by
Mikola
silly reasoning... if you don't get a new one you will never know if it's just an issue of your engine...
anyway you are the only one posting this problem on gas engine forums. good luck
Mike.
------
There are not so many GF40 sold since May 2013.
On this forum no one GF40 owner replied yet.
On the other forum, where I started thread at the end of last season I just got 3 replies from GF40 owners and it is in over 6 months by now, statistically speaking it is a bit premature to say that this issue is only with my engine.
Also those 3 GF40 owners reported that they mostly used engine with 50-70% throttle, but in my case I have been using engine about 30% of the time at 100% throttle. I believe it make big difference in temperature around exhaust rocker and where oil is evaporating .... reducing lubrication. At the end of last flight I opened rocker cover right away before engine cooled down and I did it intentionally to check lubrication.
I found that rocker on fuel intake side is very well lubricated, but at the same time the rocker at exhaust site is absolutely dry!
One non-surgical thing I'd like to try is to put larger prop in order to reduce RPM at full throttle ... more-less saving overall system thrust. I have noticed thar RPM grow with the same prop by about 500 rpm since braking in period due to moving parts loosening more and more in these 10 hours in operation. At this time it is on the upper boundary of the recommended rpm, thus in the air it is ~500 even more.
High rpm may be a contributor to the issue although I am using Saito engines in the same manner for a long time w/o any issue with lubrication.
Any GF40 owner is reading my post ?
AK.