I just purchased Tower Hobbies .46 engine.
I broke it in as the directions said. The problem is, right after the plane takes off and goes for the first turn seems that the engine loses power and stalls.
Also I get little air bubbles in the fuel hose.
What should I do???
Thank you,
Valdis

The engine is getting too lean on you. It could be the needle valve is not open enough or it could be your tank is vibrating against something hard or you have a hole in your fuel line.
Jim

I agree with Jim - you probably have a hole in your fuel line somewhere between the clunk and engine.

Do you have a long distance from your tank to your engine, and are you using muffler pressure?

Have you had a helper hold the airplane vertically and run the engine at full throttle to see if it goes lean at that point?

Lynn

One other thing to check is your prop balance. If you are really vibrating, this may the fuel foaming.

Valdis Wrote: "First of all, thank you for advice.
I tried to hold the plane vertically with full trothle and sometimes it stalled. What does it mean and how can I fix that? Other times the engine did not stall and it flew great. I had a long distance between the fuel tank and the engine, but I cut it shorter. Did I do right?
Other wise I had couple great flights today,
You made my day!
Thank you

Valdis"


Valdis,

Yes, the shorter run will help.

When it stalled out when holding it verticle, the engine was going lean. Try opening the needle valve a couple more clicks and try it again. Your engine is always going to turn more rpms in the air than it does on the ground, so you should always be a little rich on the ground to prevent frying your engine while flying.

If it continues to die out when holding it vertically, you either do not have enough muffler pressure, you have a kink/other restriction in your fuel line or an air leak.

Are there any air bubbles in the line?

Have you removed the needle valve from the body and pumped some fuel directly through the fuel inlet to flush out any dirt, tubing flakes, etc from the needle valve body?

If these check out good, then check your carb seating - loosen the carb retaining bolts/nuts, make sure the carb is pressed firmly into the engine body and the o-ring is seated if you have one, then tighten it back up.

Another location where some of the carbs leak is at the needle valve itself. This can be cured by using a 1/4 inch or shorter section of fuel tubing. Removing the needle valve, slide the fuel tubing over the sharp end of the needle valve up on the threads, and screw it back in so the tubing butts up against the the carburator body when the needle if properly adjusted.

Lastly, a weak glow plug can die out from vibration at the top end. Try another glow plug and be sure to balance your prop.

Lynn

What prop are you using_bob