Carburetor problems
 

On my O.S. Max 40 engine, the throttle lever retaining screw came loose and prevented my engine from operating properly. After tightening the screw, it worked fine for one day. The second time I went to fly, the engine stopped shortly after starting and also in mid-air resulting in a dead stick crash with no damage. Why does the carburetor not have the same opening every time I move the stick to the low position? Sometimes the opening is smaller then needed to idle the engine and when this happens, the engine shuts down to disastrous results.

I contacted O.S. and they said that I need to either flush the carburetor with fuel or get a new one. Does this make sense? It was hard to get it out of them, see a little difficult to work with.

Thank you for your help in this matter.

RE: Carburetor problems
 

LokiDog,

If your carburator does not have the same opening at different times without having changed anything in the transmitter in regards to throws or trim, it is likely that you have a problem with the servo gears. The gears might be jumping one of two theets in both directions. I had the problem myself one time. I remember that idle was either too fast at times and too close at other times. Replacing the gears of the servo resolved my problems.

I hope it helps.

Pedro

RE: Carburetor problems
 

Sounds as though its the earliar bleeder or an LA carb with a simple set screw to secure the throttle arm to the throttle barrel with no midrange needle in the middle.

If so, from your description it would seem that you simply have not tightened that screw enough. As there is no convienient way to secure the throttle barrell when tightening and that screw is a cross tip screw (difficult at best).

Perhaps one way is to just use a wood dowel that just fits into the venturi enought to reach the barrel and secure the barrel that way as you tighten the screw with a good crosstip screwdriver that fits.

John

RE: Carburetor problems
 

your throttle linkage might be binding up and flexing instead of moving. is it a solid pushrod or cable connection. does the solid pushrod go through a curved path pushrod guide.

RE: Carburetor problems
 

Solid pushrod through a guide, don't know if it is curved, I'll have to look. I seem to remember it was pretty straight. I don't think it is binding and flexing.

RE: Carburetor problems
 

Then, it is a barrel that is not free to rotate and / or a faulty barrel-lever connection.

Here is the manual for your engine:

http://manuals.hobbico.com/osm/40-46-65la-manual.pdf

Check page #18 for proper location of the lever respect to the barrel.

Disconnect the linkage and move the barrel all the way back and forth.
Pay attention to any restriction, while you pull it and push it at the same time you rotate.

If needed, back up the retention screw for the barrel.
If it needs to stay out, fix it in position with some thread lock compund.

Clean the surfaces of the lever and barrel where they make contact, and screw both tight as indicated by JohnBuckner above.
If the connection is not solid to your touch, then we need to worry about that screw's thread.

Regards!

RE: Carburetor problems
 

I will give this a shot. Thanks!!