912 fuel pump drain routing

The same warning applies to the carb vent lines. So if the manufacturer did their homework, placing the drain line next to the vent lines would seem an okay technique.

You can run the fuel pump drain line back up under the 1&3 cyl. to the back of the firewall. It should have a downward angle all the way back and down the back of the firewall. Do no put it out into the slip stream. Cut and mount it back up inside the bottom of the cowl lip about 2" or so. It isn't an exact measurement, juts not in the slip stream. You may never see anything come of the the tube, but may see a drop or two. 

Roger, what type of drain line hose (e.g. material, size, length) do you recommend and where to purchase? Also, what type of container do you recommend to mount and catch the drainage with? I would assume it has to be some type of material that won't melt and/or degrade under high heat.

I don't see any documentation other than the outside diameter (6mm) and the slip-on length (22mm) from the Rotax install manual. 

Thank you in advance!

Hello all

the nipple size is shown and the push length for the hose is shown in the installation manual.  The number shown is not the outside diameter it is the inside hose diameter you need to use.  

Common practice for all drain lines is to notch the line somewhere within the nacelle before it exits into any low pressure area.  (Best practice AC-43-1B for drain lines) 

Cheers

Its called a drain hose, however its main function is to warn the pilot of a developing/impending fuel pump failure, secondly, to allow escaping fuel/oil to exit the pump housing.

The usually small leak that indicates an impending pump seal failure is easy to miss, if the line just exits into free air. To see/witness any small leak, the fluid must be caught ("catch-can") & held until the pilot does his/her next pre flight inspection.

I rout my hose into a catch-can/ small clear plastic drink bottle. The bottle top is drilled for the hose to make a tight fit and several small "breather" holes are drilled around the neck of the bottle. The bottle is secured using Velcro tape onto a convenient part of the engine mount, low down on the firewall close to my gascolator inspection door.

Most difficult part is sourcing a suitable empty soft drink bottle. Worst case scenario is drinking the toxic contents, safest bet, is to dispose of in an environmentally friendly way?