Marvel Schebler MA4SPA Carburetor leaking fuel

[F1R]

Marvels with a few (900 hours) hours of service often vibrate the float bowl section of the carb loose. There is an AD on this. With the cowl off ( at every oil change) just lightly try to wiggle the bottom body of the carb sideways. You will know instantly if it is loose. Any time a Marvel has a fuel leak of any kind show up, it is the first thing I look at.

Mahlon 's opinion / advice is 100% good. ( post #20)

[Ramiro Silveira]

Mahlon,

I have always checked and it is perfectly attached to the engine.
I agree with you that I should not run the risk to damage my plane and my self saving money on a decent carb.
I am looking for a new one.
Thanks,

Ramiro

[CAVU Mark]

Did you find a new carb? Did you do an autopsy?

[lr172]

Originally Posted by Ramiro Silveira

And why a few amount of fuel would leak through the airbox few minutes after flight during engine cooldown period with mixture in cut off and throttle closed?
Regards,

Ramiro

I can only think of three reasons a carb would leak into the airbox after shut down, assuming you're not moving the throttle. First is a crack. Second is continued fuel flow into the carb under high pressure or low pressure with a bad needle/seat. Third would be a poorly adjusted float level (level too high causing overflow out of vent into throat), but you would be running overly rich without agressive leaning. Someone needs to check this carb for a crack. Given your previous problems, I would be looking in the area of the accel pump chamber.

Larry

[rvbuilder2002]

My guess would be a sinking float.

Causes engine to run overly rich and will dump fuel into the FAB.
It can get bad enough that the engine will quit on roll-out after landing because it has been idling on final with a very rich mixture.

[Ramiro Silveira]

To make a long story short: I sent the carb to Marvel Schebler and no issues were found.
I am not surprised with this result because the technical problem was intermittent, it happened to me few times, but it did not showed up at manufacturer shop flow test bench.
I preferred to not run more risks test flying this supposed fault prone carb then I ordered a rebuilt one and took US$600.00 as core change refund.
By now it is installed but tested only on the ground.
It is running fine until now.
Flight test to happen soon...