New Rotax 912 Fuel Pump

[Dave S]

Good afternoon,

In the process of doing the rubber parts replacement on our kitfox, I am installing the new version of the rotax 912 mechanical fuel pump which has a nipple on the bottom the old one did not. I guess if the diaphram on the old one ruptures, the gasoline just drooles down on the exhaust :eek: while the new one conducts the leakage trhough the nipple & attached tubing and away to some less exciting place :).

What I am curious about is what people are using for the drain tubing in this application and how they have chosen to route drain line. Also curious if there is any problem if the line does not flow continuously downhill.

Sincerely,

Dave S

KF 7
912ULS Warp Drive

[foxy]

this is what Rotax says

http://legacy.rotaxowner.com/si_tb_info/serviceinfo/si-912-020r7.pdf

section 73-00-00 page 9 of 14

use a tubing made for fuel

[Dick B in KY]

Dave, I used a piece of Barricade to get from the nipple to a metal line . Routed the metal line on right side of cowling to the firewall and down (away from the exhaust pipe). No problems so far.

Dick B

[Dave S]

Dick,

I like the idea of the metal line with connectors. Curious....what type of metal tube did you use?

From what I see on our plane - the right side looks like where it should go in my case also.

Having just had our 66 Mustang fuel pump start to drool gas in the engine compartment through the weep holes:mad:....I really like the idea a diversion drain.

Passing along a couple install/testing things I did....1) the new pump gravity drains 11.25 GPH at the outlet of the pump with full wing tanks - I was suprised as the old one was about half that for gravity drain. 2) Using a test gauge...the new pump holds 6.25 PSI on its own...with the electric pump turned on, it comes up an addittional 0.25 psi. The spec for the pump is 2.2 - 7.26 PSI, I believe. My old mechanical pump always delivered 5 psi - again with about 0.25 psi addittional with the electric pump on also. 3) The pump plunger on the old pump and the pump cam on the engine both had a smooth/shiny appearance with essentially no wear.

{some day I may put in a fuel pressure gauge on the panel}

Thanks,

Dave S

[Dick B in KY]

Dave, I used a 1/4" soft aluminum metal line - easy to bend as required - (purchased from a plumbing suppy house for use on a water heater). Cheap, easy to work, etc.

Dick B