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You don't know what's inside?

Roger Lee

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Hi Guys,


I just happen to get a hold of a Rotax fuel pump and a Rotax oil pressure sender and I just couldn't resist the urge to explore. So out comes the saw and presto the guts are exposed.

If you look close on the oil pressure sender you can see a plunger just under the center of the main arm and when pressure pushes on it it in turn moves the arm, which is held down by a spring until the pressure pushes and that moves the rheostat lever which changes the resistance which is then calibrated for your oil pressure gauge. Damn this is hard to follow.


The next pictures are of a Rotax fuel pump. Once the housing is removed you can see an inner plate that has a screen mounted to it and that screen went up into the outer chamber of the pump. The diaphragm separates the two outer chambers where they meet the pump aluminum mount. (It is where the gold metal meets the aluminum.) The fuel is sucked into the inner chamber by the motion of the diaphragm and as the diaphragm pushes back up the one way valve that the screen sits on closes and the fuel is then forced out the

output side of the pump. There is another picture of just the diaphragm still in the aluminum pump housing. The inlet to the pump is the larger of the two nozzels mounted on the pump. The fuel out nozzle is the smaller of the two nozzles.


If none of this makes any since, it didn't to me either and I typed it.:unsure:

Cut Rotax oil sender.pdf

Cut Rotax fuel filter.pdf

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