Engine dies

[mwebb]

Rebuilt my A4 due to a cracked block. Now another problem. Engine starts and runs at the dock and have run it for 1/2 hours with no stalls. After leaving the slip it ran perfectly but about a 1/4 mile out on the lake, then the engine dies while at 1/2 throttle. Started right up but kept stalling at both idle and all throttle settings after running a couple of minutes. No noticeable surge or power loss before the sudden stall . Choke must be used to start even when warm which is odd. Batteries depleted due to repeated startings and I get a tow in. After battery charge, engine starts next day and idles for 15 minutes, no stall. I figure water in gas due to increased tank movement out on the lake but also guess that the engine wouldn't then start right up without a whole bunch of cranking. It starts right up. Anyone have any ideas?

[Don Moyer]

mwebb,

My first guess is that your fuel supply is defective. There is apparently just enough fuel getting to your engine to keep it running at lower power settings in the slip, but under power the fuel level within the float chamber of the carburetor slowly depletes until the engine stops. It could be nothing more complicated than a blown fuse in the electric fuel pump power circuit.

Don

[mwebb]

When the engine was rebuilt, the rebuilder used the oil pressure sensor for the power to the fuel pump but instead of hitting the hot side of the sensor (who connects directly back to the 12 volt pole on the coil) he connected to the other side of the sensor. I'm not sure what voltage, etc., the fuel pump was getting but it sure wasn't enough to make the fuel pump work. It seems to be now making appropriate pumping noises. Thanks for the help.