Echo CS 3400 only runs when choke is on

[Ant411]

Hello everyone

Have a echo CS 3400 chainsaw. Just rebuilt the carb and changed all the lines and fuel filter spark plug. Saul runs excellent as long as the choke is on. As soon as I take the choke off it dies. I am thinking it's sucking air somewhere else am I correct? Any help is appreciated

 

[boltonranger]

If you’re satisfied the carburetor is all set maybe vacuum test your case.

 

[s sidewall]

Why was the carb rebuilt and lines replaced? What was it doing before this was done?

Steve

 

[Bobby Kirbos]

It could be something as easy as the carb being set WAY too lean.

 

[Ant411]

Why was the carb rebuilt and lines replaced? What was it doing before this was done?

Steve

Why was the carb rebuilt and lines replaced? What was it doing before this was done?

Steve

All the fuel lines were brittle. So I ordered a carb kit that came with the plug the filter the rebuild kit for the carb..

 

[rmh3481]

First, clean out the exhaust screen. They plug up with carbon. Remove the cover screws and then use a propane torch and a pair of pliers to hold the screen. After your sure that is clean if its still hesitating open the low screw on the carb (closest to the cylinder) a 1/4 a turn and try it again.

All carb adjustments should be done from a reference. For instance, pull the limiters and then close each of the jets counting the turns in to lightly seated. Write this down on a sheet of paper. Return to where you started and open from there.

Also, the carb diaphragms are going on 15 years old so they should be replaced. They get hard from the alcohol in the fuel and wont move like the should.

 

[Ant411]

First, clean out the exhaust screen. They plug up with carbon. Remove the cover screws and then use a propane torch and a pair of pliers to hold the screen. After your sure that is clean if its still hesitating open the low screw on the carb (closest to the cylinder) a 1/4 a turn and try it again.

All carb adjustments should be done from a reference. For instance, pull the limiters and then close each of the jets counting the turns in to lightly seated. Write this down on a sheet of paper. Return to where you started and open from there.

Also, the carb diaphragms are going on 15 years old so they should be replaced. They get hard from the alcohol in the fuel and wont move like the should.

Okay I clean the screen before we even started talking but I did it again anyway it looks spotless. The carburetor adjustments are like locked with these red locks on them should I take them off? Also carb diaphragms are brand new

 

[rmh3481]

Yes the red carb jet screw caps have to come off. Use a drywall screw and turn the caps so that the tabs line up with the slit in the cover. Mark down where each jet is currently set by counting the turns to lightly seated clockwise. .

On the diaphragms, the gaskets are reversed from the pump side to the metering side. Pump side is one center screw. On the pump side the diaphragm goes down against the casting first, followed by the gasket and then the cover. On the metering side, the gasket goes down first followed by the diaphragm and then the cover.

 

[rmh3481]

Most of the 3400's have a small reed valve in the intake stack. Its a flat plate about the size of a dime, or slightly larger. As long as the screws are tight, chances of an air leak in the intake are low. Ive seen debris in the reed but only where the engine was run without an air filter?

Crank seals are fairly robust on these so an air leak at the crank chances are low unless its got a whole lot of hours on it.

Mark where the L/H jets are now and then open the low side in 1/4 turn increments until the transition is normal. A correctly set Low circuit will be slightly rich to provide for the transition meaning the engine will not accelerate off a lean low circuit.

 

[Ant411]

Yippee. I knew this saw wasn't a paperweight. That did it. It was the adjusting screws. I cleaned them all up inside there with carb cleaner put them back together. Put the carb back on she fired right up. I need a small screwdriver to do my final adjustments though it's hard to get in there. But she's running the rest of it's just adjustments thank you very much guys..