Ok…where to start. I am so frustrated at this point I don’t know what to do….and I hate “giving up”.

My Heli:

Raptor 50
O.S. 50 Hyper
O.S. #8 glow plug
Standard tank with a header tank
Hayes black clunk line

So a while ago, while flying the engine simply cut off at about 30 feet up. I did a semi-auto and only broke the landing gear. At the time I had a standard O.S 50 sx-h (non-hyper). I fixed the landing gear and while I was at it, installed a Throttle Jockey Pro Governor and from this point on the heli has never been the same.

The problem: It starts fine, but as soon as I get to about ¼ throttle, the engine cuts off immediately.

Things I’ve done:
- replaced glow plug numerous times
- replaced ALL fuel lines
- replaced ALL fuel clunk lines
- messed with the richness/leanness to no avail
- replaced the main tank
- and last night I freaking replaced the engine with a O.S. 50 Hyper

Where I stand now: After replacing the engine with another one (O.S. 50 Hyper), I’m STILL having this issue! So now I can eliminate the engine and messing with the needle valve, etc. But I’m out of things to try now! The ONLY things I haven’t replaced are the muffler (but it appears to be fine), and the header tank (but I’ve removed it for testing and still had this issue). I tried it without the governor in the loop by plugging the throttle servo directly into the receiver with the same result.

What the heck else can I do? As you can see, I’ve replaced just about everything! I miss my Raptor!

Thanks!
Skarn

try adding a glow driver, and see if it cuts out then as well. If it does not. I would think your idle mixture is too rich, or your plug is too cold. Try an Enya #3 or OS-F plug

Hi!
Have you set the idle mixture??
How much nitro do you use? I have notion that these engines are made to run on max 20% nitro.

Nah they run fine on 30 percent.

Mail me the engine or the heli, I'll fix it and send it back.

You have a fuel problem. It's either the fuel itself or a delivery issue.

Have you tried a fresh can of fuel?

Is the pressure nipple on the muffler partially blocked? Pull the muffler, blow into one end and cap the other. You should have a nice steady stream of air coming from the pressure nipple. Try cleaning or drilling it out with the appropriate drill bit.

Put a new piece of fuel line on the carb and blow through it. Work the throttle up and down. Does the air flow proportionally to the carb setting?

Is the governor working correctly? Have you tried to run the motor without it since the trouble started?

pe reivers: I tried what you suggested....I had to borrow a battery one since I do use a field box one with wires.....but I'll be damned if I finally did get it to hover for about 10 seconds before it completely quit again. But then I had problems even getting it to start after that and I was frustrated so I put it away for the night. So I was going to replace the glow plug the next time I mess with it. But if it's too rich, wouldn't it sputter first then quit, not quit suddenly.....I though too lean would indicate the sudden cut?

Skarn

It is not always clear why an engine quits that way. Too rich, and it may just cut out, but it also does this when too lean, or the fuel is stale (previous post) or the plug is contaminated, or the plug is the wrong heat grade or heat retention.
The fact that the engine would hardly start, points into the direction of too lean or contaminated glow element. It should sputter and pick up if you have additional glow power applied.
Use the pinch method to determine mixture. Pinch the fuel line. If the engine dies without picking up speed first, you are too lean.

There's only about 100 posts about this across the various forums...

He sealed the muffler with RTV, my (and others) guess is its getting sucked into the combustion chamber and snuffing the plug.

My offer stands, send me the motor, it will save you a lot of typing

No only 4



Update: It's finally working!

What I did...three things actually:
1) Blew through the muffler pressure release nipple to ensure it was clear
2) Replaced glow plug...once again.
3) Tried new batch of fuel.

So...not sure exactly which was the culprit....but I suspect the glow plug! The new engine I got I never replaced that plug because it was glowing fine. But since it was having problems even starting lately, I replaced it with an OS 8. It's possible it was the fuel since I had been using the same last bit from a gallon...I'd keep draining it and putting it back into the bottle...then back into heli etc. Lastly I guess it could have been a clogged pressure fitting on the muffler but hard to tell....I didn't have resistance when I blew through it.

But it's back! Thanks everyone for the ideas and help!
Skarn