Completed the Fuel Pumps & Naviflow Assembly

TLDR

• Made a new flaring tube to fit the fuel pump assembly better
• Tightened all connections and finished the assembly
• Installed the naviflow unit

Details

Fuel Pumps

Continuing from last week’s saga, I decided to change a few Sling provided parts on the fuel pump to fully stay in compliance with Rotax’s instruction.

• Instead of 1/8 NPT fittings on the pump outlet, I switched to M10x1-6AN fitting
• Instead of 2 washers said by Sling, 1 crush washer only.

After I tightened the fittings on both ends of the pump, I connected everything except for the flare tube.

The assembly is symetric, and the flare tube on one side fits pretty good, so I just went ahead and tightened it all the way down.

On the other end, the tube was too long. Yes it’s too short last week before I tightened everything but now too long. So I cut a chunk of aluminum tube and just made a new flaring pipe. The new pipe fitted almost perfect.

With that, I finally completed the entire assmebly. I will bring it to the hangar in a few weeks and install it on the airplane.

Wiring consideration

A minor detail on the next step (wiring). After completing everything I noticed the wire terminal of one of the pumps is right behind the fuel line fitting. I am not sure how much clearance I have on the airplane but it’s probably not a lot. So I might have a problem connecting the wire there. Next time I go to the hangar, I plan to take a look. Worst case I will make the wire connector off the airplane first, then install the assembly.

Naviflow

I also finished the naviflow today.

The only remaining work really is just to torque the 2 banjo bolts and install the whole unit onto the firewall.

I elected to first install the unit, so the whole thing is tightened to a flat surface. Then I torqued the bolts per the instruction (M12 15 ft lb, M14 19 ft lb).