TT50 motor problems

[Hein]

Ok guys I have had a problem with this TT50 motor since day one. Please help I have had guys at my local club check this out but seems it is impossible to isolate the cause.

Fuel 15% nitro also tried 20 and 30%(30% seems to run pretty good and better performance) changed glow plugs (2xOS no 8 and 1xEnya no3) enya seems to work much better. Tried adjusting the pitch curve when the head speed increases seems to work somehow does not seem viable adjusting this every time. Tried lowering the throttle curve down also seems to work but starting still a problem.

What happens.
Low-end needle adjusted so the motor idles, 3.5 turns on the main needle. Constant height hover approx 10 seconds first say 8 seconds all is well but after the head speed gradually increases up to the point where the heli becomes unstable.
Set it down keep adjusting the low-end needle so it idles ok and head speed does not increase. Motor then runs and idles cool but a bit sluggish in the hover. Cannot lean the low end for performance due to the head speed increase problem.

Fuel up and cannot start/idle the motor due to the low end being too rich. Lean out the low-end needle to get it to start/idle. Constant hover same head speed increase as above once again need to richen the low end needle too get it to not increase the head speed.

Tuning and burning fuel mostly adjusting the carb not flying?

Taken the motor apart head gasket seems to be installed. Did notice the muffler gasket may not be sealing properly. Taken the CARB off checked the O-ring seems ok, cleaned out the carb once, checked the fuel filter seems ok. Checked fuel lines in and outside of tanks all seems ok. Not tried running the motor after taking it apart will do it this weekend.

I know this seems like a long post but I am desperate PLEASE help!
:arggg: :arggg:
:arggg: :bomb: :bomb:

[Alfred]

Is this a new engine?
How many runs has it had so far?
The TT's are all over the place until they have run in a bit.
Also remember that the TT50 is not a OS Hyper...you might be expecting too much in regards to power and you are leaning her out too much causing thermal runaway, which would explain your headspeed increasing in hover.
The idle needle is your main adjustmend needle with the main needle just looking after the very top end.
Why you can't get her to idle when set rich enough, tells me that you most likeley have your throttle linkage symetry wrong.
With other words, the barrel just doesn't open far enough when the throttle trim is set to high.

[StillTryin]

The TT "needle mod" is probably your answer. I broadens the sweet spot.
I have done it and I must say, the modified TT50 is as well behaved as any other engine, albeit, not as powerful as a Hyper. But then again, it uses less fuel too :)
The mod details are on RunRyder at: http://www.runryder.com/helicopter/t86466p1/?highlight=tt50+needle+mod

Easiest for me was to chuck the needle in a light drill and then touching it down onto a belt sander while both sander and drill were running. Go gently!