One more item. There is a Service Letter regarding the fuel crossover pipe under the seats becoming bent or kinked by the flap lever or by stowage of hard objects under the seat. There is also a Bulletin regarding the pinching of the fuel pipes leaving the tanks by overtightening of the hose clamps.

Jeremy

Thanks for that information on the different fuel pressures. That is good information. I assume that is with the boost pumps off.

Is the fuel pressure taken before the engine driven fuel pump? Does the engine driven fuel pump have a bypass in case of failure? If it fails, will it drip fuel out of the drain line? Mine does not do that but I would like to understand it more. The engine should run fine without the engine driven pump except maybe for steep climb attitudes.

I will definitely try the fuel pressure test as soon as the weather allows.

I do my own fueling so I do know how quickly the fuel equalizes in Both or Off.

When are you going to write a manual with all of your knowledge.

Thanks

flyer

Fuel pressure is taken at the carburetor after all pumps. Check pressure with boost (Dukes) pump off. If you switch boost on you should see a rise. If the engine driven fuel pump is not working because of bad valves or dirt, the boost may be able to push fuel on through, but if it is a leak in the diaphragm then fuel will port overboard. If eng. pump is not working but clear, gravity from the tanks may be able to supply enough fuel, however do not rely on the boost pump to get you home as it is not designed to run continuously and won't.
The lowest allowable pressure is shown in your Lyc. engine book which should be in the plane for operations. The Maule parts book though sparse shows your complete fuel system.
The primer takes it's fuel from the gascolater so the pumps don't affect it, however if the primer plunger leaks, air can be itroduced into the cylinders.

I've had similar problems. Probably just flying on "both" and Chinese pilot - Wun Wing Lo.

LMFAO!!!!!

Jeremy;

Did I understand you correctly to say that when the fuel valve is set to "Off" the left and right tanks will crossfeed?

Tom

Tom

I think that is correct. If the crossfeed is in both or off, the tanks will crossfeed. I learned that the hard way as I do most things.

Do not try the off in flight. duhh

flyer

The older Maules don't have a both, just left, right, and off. Both types of valve will crossfeed in both. The latest Maules for 2007 and a few in end 2006 have the latest,latest fuel valve, a thing of beauty but I have not tested its idiosyncracies yet

I retrofitted my M5 (1977) w/ a L-R-B-O valve.

Best I can figure the tanks don't feed evenly worth a damn. I am guessing differing pressures wing angles, phase of the moon, etc.

I agree that L or R is the way to go unless making steep turns or on landing where you don't want to attempt to wean the Lycoming.

Tom