Fuel Line Replacement...

Hi Michael,

My 200hr 912ULS uses Gates fuel hose, all to "barb" fittings, as did my last 912ULS, that was 950 hrs when I sold the aircraft. Its a perfectly legitimate way of attaching hoses and safe if done correctly.

If you are going down the "barb" track use only automotive style barbs, not the old multi barb type.

When selecting the hose size, get the correct OD hose for the ID of thefitting. The objective is for the hose to make a fuel tight seal, without the need for a clamp. The clamp is for security, not sealing a badly fitting hose.

In the above example, the OD is of the smooth pipe (not the bulge/barb). A correctly sized hose will fit snuggly to the pipe and have enough elasticity to go over the barb. 

Fitting can be made easier with a smear of silicon lubricant. 

Hose length should always be such that the hose  goes right up to the end of the fitting, without needing to be put under tension.

Hoses should be supported ie not place undue weight/movement on the fitting.

The clamp , located just to one side of the barb (bulge) only so tight as to prevent the hose slipping off the fitting.

The above style fitting (& many more) are available from most automotive parts supply stores, particularity those offering performance parts.😈

No shortage of banjo bolt sellers, just Google it.

True but I have been trying to find the specific dual hose barb banjo which doesn't seem to exist in the size for Rotax unless you buy their $400 one.  You can see in the image.  I haven't had issues finding the single banjo fittings but that dual one is elusive.

If you have any links I would be grateful.  I need the banjo fitting for the fuel block that feeds both the carbs.  I believe the ID of the barb needs to be around 1/4" per Rotax.

Do you have photos of links to these banjo fittings?  I have been able to find the single ones but not the dual sided one for in between the carbs.  See the photo.

Hi Michael,

I think the Rotax banjos you are referring to are 8mm.

The following would require installing an alternative to the Rotax “fuel distribution block”.

If you were able to increase the size for your “custom” system to 10mm, I think the parts would be more readily available.

Here are 2 double banjos, one is AN3, the other is AN4.

All the other banjo components, hose and fittings you would require for an “AN” installation are listed on the web site below. I have used some of their products and have found them to be of good quality.

I hope this helps.

Cheers, Des

https://aeroflowperformance.com/af310-03-03l-10mm-3-8-banjo-double-3an

https://aeroflowperformance.com/af310-04-04-10mm-3-8-banjo-double-4an

P.S. This is certainly less than elegant however adapters are available to reduce from M10 to M8. For example:-

https://simplefix.co.nz/wp-content/uploads/2016/07/BIS-Thread-Adaptor-M-F-OUR-EDIT.pdf