have osfx.25 on sturdybirdy broke engine in with help of hobby shop guy engine runs great is hard to start dosent like comeing past 1.4 throtle till its run 2min. its real touchy dies restarts dies restarts then it starts and runs good tunes good do pich fuel line check for high and low settings and its good to go put her up she flew dead sticked got her down ok wants to restart but wont gave up for to day will probly run again but should i have to play around with it so much every time i want to run it how long to warm up engine are speratic air bubbles a problem seems to runn good sometimes and thier and sometimes it wont run good and their are bubbles in fuel line its been 35 to 45 deg out during its run life to day with first dead stick it was 45 deg what am i doing wrong help this is my first engine

Sounds like your mixture is too lean. Open the High speed a couple clicks and if that doesn't fix it, open the low speed about 1/8 turn.

My friend has one and you couldn't ask for a nicer engine.

Enjoy,

Jim

The first thing to do is unlearn the "fuel line pinch". It is extremely inaccurate and tells you nothing about how the engine will run in the air while climbing. Adjust your high speed needle for peak RPM and then set the needle richer until you can clearly hear it slow down. Once you are at this setting, get a firm two hand grip on the plane and point the nose up. If the engine speed drops, you are too lean, or your pressure line is not working. Immediately put it back on the ground and set it richer. If the engine speed stays the same, you are a bit too lean. The plane will probably be ok at this setting, but as the tank empties, it will lean out more and you will probably dead stick. If the engine speeds up a little, the setting is pretty good, keep the nose pointed up for at least 5 to 10 seconds to confirm the RPMs don't begin to drop off.

Next is the air bubbles. It wasn't clear from your post if you were seeing these while the engine was running, or if they were in the line after a dead stick. Can you clarify?

saw air bubbels while engine was runnig held plane straibght up at full throtle rpm,s stayed same tuned high end to peak rpm then ccw 4 clicks low end was set at just over to turns out when i got it went a 8th turn both ways trying to correct problem

Is it possible that your engine is cowled in?

What prop are you running?

Enjoy,

Jim

9x6 prop no its not coweled

Only thing I can think of is that there is something wrong with your tank or you wouldn't be getting the air bubbles? There's probably a pin hole or slit in your fuel line?

Enjoy,

Jim

That's be my guess too. If it's getting bubbles when held vertical, but not when level, a hole in the tank line is the most obvious candidate. If it happens when horizontal, it could be the outside lines.

One more possibility. I do remember reading a post here one time about a crack in the remote needle assembly that resulted in air bubbles in the line. These would only show up in the line between the needle and carb. This might happen when vertical but not horizontal due to the extra suction required to lift the fuel. One more needle valve possibility is air leaking past the needle itself. I've had to add a short length of fuel line on some other types of engines to reduce this possibility.

Also make sure the tank is not touching the fuselage any where as the vibration will cause the fuel to bubble. May only do it at a narrow RPM band.

thanks for the help isolated the tank set the high end 3 clicks open richend the low end checked by holding it straight up prop to the sky rpm's rose 300 and stayed their transitons great no more air bubbles thanx

Glad to hear your problem is resolved. Happyy flying.