O.S. max la .25 fuel line question

How many fuel and air lines connect the engine and where do they connect to, Thank You.

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O.S. max la .25 fuel line question

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Jul 12, 2010
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Hey Michael...
by: Matt

Hey Michael from Oz,

Over the past year or so you have been a great help and valuable resource for answering questions related to engines. Just wanted to let you know that I appreciate it. I would have contacted you privately but I don't have your email address.

I have just started a forum and I was hoping you could register a name and introduce yourself in the welcome section.

Hooked on RC Airplanes Forum

Thanks again!

Matt

Jul 11, 2010
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Two or three
by: Michael from Oz

G'day

Your engine has two connections to the tank. The fuel tank can have two or three.

The engine has a fuel inlet on the carby. This goes (as the other poster said) to the outlet from the tank which should be connected to the Clunk via a piece of flexible tube inside the tank so that the clunk is about 1/4 inch forward of the back of the tank and free to move up, down and sideways. On tanks with only two connections, I fill my tank through this fuel line by removing it from the carby and inserting my fuel pump line.

The other connection is on the muffler. It sends pressure to the tank to help the tank supply fuel to the engine more evenly. This connection should go to a pipe which you bend to go to the TOP of the tank. This will allow you to empty the tank through the same line you fill it and the top tank line will then act as a vent to let air in as the fuel goes out.

You can use a third line as a filler line. If you do, it should go to the bottom of the tank and be blocked when the engine is running. You can also drain the tank by this line.

If I can easily get at the engine, I use the two line setup as it is simpler. If I have a cowled engine, I use the three line setup and bring the filler line out under the plane where I can get at it easily.

If your tank is rather tall, you can add small pieces of fuel tube to the brass tube to make them reach the top and bottom of the tank.

I use colour coded tubing. Clear blue for fuel to the engine, clear red for the pressure line from the muffler and green for filling. Makes things easier because if you mix the lines up, strange things happen.

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Jul 11, 2010
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Submitted by: Michael from Oz

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G'day Your engine has two connections to the tank. The fuel tank can have two or three. The engine has a fuel inlet on the carby. This goes (as the other poster said) to the outlet from the tank which should be connected to the Clunk via a piece of flexible tube inside the tank so that the clunk is about 1/4 inch forward of the back of the tank and free to move up, down and sideways. On tanks with only two connections, I fill my tank through this fuel line by removing it from the carby and inserting my fuel pump line. The other connection is on the muffler. It sends pressure to the tank to help the tank supply fuel to the engine more evenly. This connection should go to a pipe which you bend to go to the TOP of the tank. This will allow you to empty the tank through the same line you fill it and the top tank line will then act as a vent to let air in as the fuel goes out. You can use a third line as a filler line. If you do, it should go to the bottom of the tank and be blocked when the engine is running. You can also drain the tank by this line. If I can easily get at the engine, I use the two line setup as it is simpler. If I have a cowled engine, I use the three line setup and bring the filler line out under the plane where I can get at it easily. If your tank is rather tall, you can add small pieces of fuel tube to the brass tube to make them reach the top and bottom of the tank. I use colour coded tubing. Clear blue for fuel to the engine, clear red for the pressure line from the muffler and green for filling. Makes things easier because if you mix the lines up, strange things happen.

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Jul 11, 2010
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Fuel lines
by: jsesere

You have a single fuel line from the output of the fuel tank to the carb. This output runs from the bottom of the inside of the tank, is a flexable silicone tube and has a brass klunker on it to keep it on the bottom. The other tube on the fuel tank is for filling the tank and is a brass tube that runs to the inside top of the tank.