updated 912 fuel pump question

[avidflyer]

I'm getting close to running the fuel lines on my Kitfox 4 rebuild project. I'm installing a used 912 that has the updated fuel pump on it. I would like to run the fuel lines over the top of the engine, but the fuel fittings on the pump point down. The picture shows the engine as it was before I bought it. You would think it would be easy to unscrew the cover screws and turn it so the fittings are pointing back instead of down. All of the pictures I've seen of the updated pump show the fittings pointing back, which would make me think mine has been turned to point down. I've reviewed the service bullitin (SB-912-063) for the change of this pump, and on page 10, paragraph 3.3 it says that the cover of the pump must not be opened for inspection. Seems to me that would eliminate turning the cover as well, but it seems someone did that on mine. Anyone have any opinion on this? Thanks, JImChuk

[Dusty]

I "clocked" mine on the original engine as they weren't in the right place. I detorqued the screws in a cross pattern then reversed the procedure to not warp the housing.No problems.

[Dave S]

Jim,

One way you might be able to tell if the cover was previously moved is to check for the presence of dabs of colored lacquer/torque seal on the cover screws. When I bought my new pump, these were clearly evident on each screw. There is always the chance that Rotax didn't do this on all of them; but, my guess is they wanted some witness mark to determine if someone had opened the cover in the event of a returned pump.

[avidflyer]

Thanks for the replys guys. Wonder if anyone runs without the fuel pump on a 912. On my Jabiru powered Avid Flyer, I just use gravity feed. It uses one type 94 bing carb with is just like the type 64 on the 912 except it's slightly larger (40 MM verses 32 MM) I do have an electric pump that I run durring full throttle ops, but a few times I forgot to turn it on and the engine never stumbled. My fuel burn is about the same as the 912, and if anything, maybe just a bit higher. The reason I got rid of the mechanical pump on the Jabiru, was it was putting out to much pressure, and would over power the float valve and flood the engine at idle. Had a couple of engine outs that way. These bing carbs were originally used on BMW motorcycles and were gravity fead. The tech guy at Bing told me they weren't designed to take much pressure. I'm not suggesting anyone gets rid of their fuel pump on the 912, just asking if anyone has, and giving some reasons for the question. Thanks, JImChuk

[skyguy04]

I’m running into the same issue with the new fuel pump. It puts out up to 7psi and LEAF says that is by design, even though the heavy maintenance manual states the carbs only expect 5.8 max psi. Our solution was to add a pressure regulator and a return line to the header tank. I don’t see why they needed to increase pressure so much. It causes all sorts of problems.


Sent from my iPhone using Tapatalk

[avidflyer]

I turned my fuel pump front cover back to the way I wanted it with no apparent issues.... Time will tell I suppose, as it will be a while before I fire it up. What size return line to the header tank are most of you running if you have installed one? Thanks, JIm Chuk

[jrevens]

I ran 1/4” OD, Jim. Don’t forget a check valve to prevent flow from the header tank back to the carburetors.