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The facet pump in my RV-6 has always rattled when I first turn it on and then becomes quieter in a few seconds. I believe it has something to do with air in the lines at first and also that there is no pressure in the line at first. Upon filling the lines and building up a little bit of pressure on the downstream side of the pump then it operates more quietly. As it works in a Q airplane there is never really any back pressure so it makes sense that it would operate a little more noisy. My RV now has about 1300 hours and is still using the original facet pump which I use only on takeoff or when I see low pressure from the mechanical pump. Since the facet pump is relatively affordable and small I carry a new one at all times. One last comment is the first 400 hours I used almost all auto fuel, since then I have only used 100LL.
On Wednesday, April 29, 2020, 9:01 AM, Jay Scheevel <jay@...> wrote:
Sorry Sam, meant to say urethane. That is what I am using in my sump drain hoses and overflow return from header, but in either case, I was just recommending Corbin only use the clear tubing temporarily to check for bubbles, then go back to his previous hose. I stated that clearly. The bubbles are easy to see in clear tubing.
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Sam Hoskins
Sent: Wednesday, April 29, 2020 9:15 AM
Subject: Re: [Q-List] Update: Faucet Fuel Pump Ticking Sound w/ Plenty of Fuel
First off, IMHO, never ever use vinyl tubing. When exposed to fuel it shrinks and hardens. This can lead to air leaks at the fittings. QAC said to use the vinyl tubing, but that was over 40 years ago.
I have found that even a very small amount of air in the lines, bubbles so small that they are difficult to see, cam make your pump rattle.
I have recently had good luck with the blue tinted urethane tubing available from Aircraft Spruce.
On Wed, Apr 29, 2020, 9:37 AM Jay Scheevel <jay@...> wrote:
Is your line from the pump to the main tank a flexible or a hard (aluminum) line? If it is flexible, I would suggest fashioning a replacement for that line out of clear vinyl tubing, then turn on the pump and look for bubbles. If no bubbles, go back to your previous line and don’t think about it any more. If it is a hard line, you may need to buy some barbed fittings for both tubing ends that will match the flared fitting size, but you can do the same exercise with the clear vinyl tubing.
Just FYI, I have two identical Facet pumps that were installed at the same time 90 operational hours ago and were new out of the box. One of them pumps the output from the fuel selector directly to the throttle body regulator and is very quiet. The other pumps from the main to the header and is very noisy, so go figure. As long as your pump is new, is not pumping air (check with temporary vinyl line), and is moving fuel at the rate you need, you should be good to go. In other words, I do not think noise is a firm diagnostic.
From: main@Q-List.groups.io <main@Q-List.groups.io> On Behalf Of Corbin via groups.io
Sent: Wednesday, April 29, 2020 7:29 AM
Subject: [Q-List] Update: Faucet Fuel Pump Ticking Sound w/ Plenty of Fuel
I couldn't find my previous thread on this so thought I would start a new one. My transfer pump (Faucet), when running with plenty of fuel in the main tank, now clicks/ticks just like when the fuel is low (air). To be sure it wasn't the fuel pump starting to fail, I went ahead and replaced it with a new one since that is a cheap and easy process. However, the new one also clicks/ticks. It seems to be pumping plenty of fuel as it will quickly start to return from the header, as normal.
So, it seems the next thing to check for is air in the lines somewhere......but how/where do I start on that?