This thing is driving me crazy, It appears to be running out of fuel. It was running fine ond day and all of a sudden it just started bogging down like it was out of fuel. If I let it sit a few minutes the primer pump will have resistance when pressed and is moving fuel. If I crank the machine and run it until it quits again the primer pump has no resistance and is not moving any fuel.

I can keep the machine running for a while if I keep pressing the primer but the bowl sems to run dry.

I have rebuilt the carb, the fuel tank is clean, the fuel strainer is clean, the fuel line is not obstructed, I checked and cleaned every part of the carb.
I did not replace the fuel primer pump but it seems to have a small tear in the boot which leaks some gas while priming.
I did not replace the fuel float either, it is not water logged and seems to be in perfect shape.
I did not replace the vacuum piston (I guess thats what it is) it had no tears in it and is very pliable.

Any ideas?????
I keep thinking the fuel float or jet is sticking but don't know how that could happen.

 

Try checking the fuel cap to make sure the vent is still working - when the cap is in the OFF position, the vent is closed - this theoretically prevents fuel from gravity flowing to the carburetor as the air volume cannot "replace" the fuel volume, therefore creating a vacuum. When the cap is in the ON position the vent is opened, allowing air to replace the fuel volume. Sometimes the vent hole in the cap gets plugged and results in the same condition as if the cap valve were in the OFF position.

You can CAREFULLY experiment with the fuel cap off the tank to see if this may be your problem.