Not sure if my issue is the regulator, but I have a 120SC inverted in a plane. When I'm done flying and stop the engine, the carb will start dripping with fuel. If I invert the plane, the entire carb fills with fuel and starts to over flow. I know I need to let the pressure out of the vent line, but my other YS engines never did that. Is my regulator not adjusted correctly? I bought this motor used. Run very well, but I want to take care of the fuel dripping.

Also, when I land the plane, sometimes I can not throttle up and taxi back to the flight line. I'm assuming the fuel is puddling from the motor being at idle for so long on approach.

Any help is appreciated.

Thanks......Mark

The dripping or fuel puddle problem you have is because the regulator is not closing. Why is it not closing I don't know. It could be some dirt or debris in the plunger seat that is keeping it open. It could be a deformed diaphram that not putting the right pressure on the plunger to help it close. It could be that the regulator is just set too rich. It could be a problem with the plunger.

Lots of options here, but its leaking fuel becasue the regulator is not closing off.

Troy Newman
Team YS

Before I flew the plane I had to take the regulator apart as the plunger was stuck (motor sat for about 2 years). Is there a procedure for adjusting the regulator? (never had to touch it on my other YS's) A friend of mine mentioned something about closing the throttle completely and blowing on one of the lines while adjusting the regulator. Does this sound familiar?

does anybody know the procedure for setting the regulator
I just bought a 140l scd hand ,i'm going to do a full rebuild
I have not had any experience with YS engines in about 10yrs - any leads to full rebuild threads ?