YS 91 SR Problem

[mattie-lodge]

Hi All,

The last couple of times I've been out with the Trex 700 I found that on the first flight, the engine (YS91 SR) runs very very lean. I have traced the problem to the one way, obvoiusly not one waying. I found this by pulling the fuel stopper out of the vent line and no pressure came out. So to cure it I have to take it to bits, blow it through and away I go again.

I think its a common fault and also I think the fix is cut the spring down slightly in the way valve.

Didn't know if anyone else had suffered the same problem?

[barney]

Hi Mattie my flying buddy has his do the same even with the shortened spring. You just need to clean it out, refit and fly.

[Steve]

I've had exactly this problem with 2 YS engines on the same day - it's the cold. When it's bitterly cold (like snow on the ground weather) then the check valve gets stuck shut - problem is made worse with a bit of gooey oil in it as well maybe. What I do now is plumb the pressure line so that the check valve is snug against the frame-side edge of the muffler - keeps it nice and warm when the engine is running.

Photo added - see how check valve is up against the muffler, and the back plate to check valve tube distance is still correct.

[Sesame]

now I see what you mean Steve. cheers

[xygax]

Guys its an idea but http://cgi.ebay.co.uk/ws/eBayISAPI.d...10df80ffde5fc9
are used for koi ponds to stop 6' head of water from getting into the air pumps they should do the excat same job mabe a soulition to ongoing problemm...

Steve