Need Help - sick OS 50 Hyper or bad setup?

[awr]

I'm having a tough time diagnosing a problem on the O.S. 50 Hyper in my Raptor 50.

New engine out of the box. No blades on because I'm still trying to get the engine to run.

When I start the engine, it immediately rises in rpm to what would be 1/4 throttle - except I haven't
touched the throttle yet. After about 3 seconds, it settles down to idle.

When I try to increase throttle, the engine dies unless I do it very slowly. When I get to mid-throttle,
the engine cuts out. In the video (see link) you can hear the engine die and then increase in rpm as
I`m increasing throttle.

http://www.youtube.com/watch?v=xqSikkP-faI

I've replaced all of the fuel tubing. Took the carburetor out and cleaned it. Double-checked the connections for leaks.

I've been told this engine will run with the needle at 2 turns (i.e. half a turn beyond normal setting), but
this engine doesn't want to run at anything past 1.5 turns.

I'm a novice to glow so I could use the wisdom of the forum.

Wayne
Calgary, Canada




p.s. Would be nice if Finless Bob did a video on this.

[DavidH]

Low end is probably a little rich also. But don't adjust it yet.
Put the main needle at a few clicks less than 1.5 turns. Between 1 1/4 to 1 1/2 turns out from fully closed.
Try that and then let us know how it runs.

David

[awr]

It's working!

Turned out to be a combination - as you said.

First thing I did was take the header tank off, so that I could eliminate that as a problem.
It had no effect so I can put that back on.

I had to lean out the low end quite a bit - about 5-7 degrees past center. I then turned the main needle out about 4 clicks past 1.5 turns so that it was running quite rich as I'm still breaking in the engine.

It now starts without flooding and there's a smooth transition to hover rpm. I put the blades on as soon as I got the needles where I wanted them and it seems to be
working fine.

I really appreciate the advice David.

Thank you

Wayne

[TheBum]

I had to lean out the low end quite a bit - about 5-7 degrees past center.
That sounds about right. Just about everybody ends up leaning the low end needle it seems.

I had a devil of a time my first time out with my T-Rex 600N. I actually managed to get the heli airborne with the low end needle at center and the high end at about 1.5 turns; it took barely perceptible throttle increases to get it spooled up, though. It was on my next outing that I learned that the low end needle was too rich. The second time I had to break in the engine (after rebuilding the engine after a nasty crash where the throttle got stuck open), I ran 2 turns out on the main needle and probably about where your low end needle ended up and had no problems spooling up.

[TheBum]

I've been noticing the other issue that the OP mentioned still persists for me. When I first start the engine, it revs up above what I would consider idle for a few seconds and then settles down into an idle. It's worse when the engine is cold, but still happens to a certain degree on subsequent starts. I thought maybe it was a too-lean low-end needle, but any attempts to richen it result in the engine cutting out when I throttle up. I'm wondering if it's normal, maybe just a combination of a cold engine and a delay in the exhaust pressurizing the fuel. Does anybody have any insights/suggestions?

[J-S-Q]

I've been noticing the other issue that the OP mentioned still persists for me. When I first start the engine, it revs up above what I would consider idle for a few seconds and then settles down into an idle. It's worse when the engine is cold, but still happens to a certain degree on subsequent starts. I thought maybe it was a too-lean low-end needle, but any attempts to richen it result in the engine cutting out when I throttle up. I'm wondering if it's normal, maybe just a combination of a cold engine and a delay in the exhaust pressurizing the fuel. Does anybody have any insights/suggestions?

Yes mine does exactly the same thing and I'm certainly assuming that the reason is just as you say -a brief delay in the engine getting it's proper supply of fuel. Would be interesting to hear if this is in any way unusual or incorrect?

[baldgeek]

Mine is the same as well.....