Fuel-line attach to Cox prod. backplate

Hey folks, "Bob" (rsv1cox) commented recently on my methods when working with fuel-lines. Today I was installing a Cox .049 product-engine (horseshoe backplate) on one of my airplanes.. and thought I'd share how I went about it. It's difficult to install a fuel-line onto the NVA/nipple "after" the engine is mounted.. or if it happens to "pull-off" the nipple after the engine is mounted. Really small ID fuel-line will usually stay-put.. but I prefer to use fuel-line that has a slightly larger ID.

This example uses line that has a .075" ID and a .165" OD. It's categorized as "small-size" line.. although "Dubro's" small-size line has a .042" ID for comparison. If your running a high-performance engine on a suction-feed.. (as opposed to a pressure-bladder..) a little less-restriction to flow can be an advantage.

That point aside.. here's what I do to help keep the fuel-line from being inadvertently/accidentally being "pulled-off" the NVA. I use a short "sleeve" of alloy-tubing that's close to my fuel-tubing's "OD".



I then insert the fuel-tubing into the sleeve. If it's a tight-fit; I apply a little petroleum-jelly to the end of the line.. and "twist/slide" the alloy-sleeve onto the line, so that there's approximately 1/4" of fuel-line protruding. Just enough to push-onto the NVA's nipple.



This can give the fuel-line some rigidity for the ease of "initial" installation onto the nipple. Once the fuel-line is installed as far as possible.. the "sleeve" can then be pushed-forward; which compresses the line around the nipple's barb. I used blunt tweezers to push the sleeve forward; being careful not to abrade the silicone fuel-line. After the sleeve is in-place, the fuel-line isn't going to pull-off unless it's "yanked-off".



It's these little details that can save a lot of frustration at the field.