LA40 Carburetor Stuck Closed

by Andrew
(Columbus, OH, USA)

I just finished building my new RC airplane. After I mounted the engine the carburetor seems to be stuck in the closed position. I would not budge no matter which way I moved the control valve. I have an OS LA40.

Any thoughts as to why the carburetor is stuck in the closed position?

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LA40 Carburetor Stuck Closed

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LA 40 Carb Stuck
by: linkadrip

I Suggest loosening the carburetor barrel screw maybe its to tight.

You can always take the carburetor off and check it. They are not really that complicated on the O.S. LA 40. I believe it is a bleed type.

Something is binding the barrel if its stuck closed. It may be gummed up with old fuel.

I notice there isn't very much information toward the condition of the engine. Is it new? Is it really dirty? Has it been plowed into the ground? (had to ask).

Many things can effect the operation of the engine components. What kind of condition is this engine in?

The carburetor only has three screws in it. One I believe is the bleed screw for adjusting the mixture. Tthe other is a barrel stop screw witch hold the barrel in the carb. And there is another screw that holds the servo control arm on the barrel.

To remove the carburetor there is a pin type pinch bolt with a nut on it at the base. Loosen it and twist and pull up on the carb to remove it.

Just my 2 cents worth.

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Carb issue
by: Anonymous

Take the carb off and put it in a pan of water with 4 drops of automatic dishwasher soap and bring it almost to a boil on the stove.

After about 10 mins or so take it out of the water and work the throttle lever and it should free up. The hot water will melt old dried up castor build up.

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What he said...
by: Anonymous

The castor is the culprit to the stuck carburetor barrel on your O.S. la engine.

You can make a stove mess for the wife to clean up, sure... But it's just as easy to remove the carb from the engine by removing the two set screws on the left and right side of the base. Then put it in a toaster oven set at 200 degrees, the same result will happen in less time.

Another thing you can also use is rubbing alcohol to free up the carb. It eats up the castor instantly. Just be sure to oil up the carb immediately and move it back and forth to disperse any alcohol (or water from the stove method) and lubricate the moving parts.

Its a bushing engine, if the carb is stuck, you probably have castor gummed up inside the case as well. Even airplane fuel will work, just takes a little longer.

Next thing to do is run the engine as soon as you can. The next time you store it, be sure to run it out of fuel and add some after run oil. It will be ready when you take it out of storage years from now.

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