Fuel Sample Question

[funflying]

Been using a Flo-Fast pump for 5 years now and I don?t believe the pump has introduced any debris. I also follow their instructions asking for oil to be put through the pump. I use a small amount, maybe 2 ounces, of marvel mystery oil, and let it run out the pickup tube as I turn the pump. I do this once or twice a year.

[Catbird]

OK, full disclosure here since you?ve hit on a sensitive topic that has caused an awful lot of frustration and embarrassment.

My RV-12 was down for maintenance, SB upgrades, and paint for over a year, finally getting it back in the air last August. Looking back, I did almost everything wrong with regard to refueling. Metal 5-gallon gas cans sat empty for 18 months. 93 octane ethanol free gas was purchased from a rural gas station that didn?t sell much gas. No filtration was used as this filth was poured into the empty tank. Within no time at all, my gascolator samples were full of enough debris to entirely cover the bottom of the sample tube. The gascolator screen was packed and fine debris made its way to the carb bowls.

With an attitude of total denial regarding the seriousness of this problem, and a refusal to remove the fuel tank again, I disconnected the fuel line from the gascolator to the engine and began pumping fuel from the tank through the gascolator into clean plastic cans. The flawed logic was that I could flush out the debris from the tank, check it with the gascolator samples, and pour the same fuel back into the tank through a Mr. Funnel. This foolishness went on for days as I wore out the fuel pumping, filtering, and sampling. The gascolator just refused to clear up.

Finally after serious some soul searching, I stopped the charade, removed thank, and opened it up by cutting off the circular access panel. What I found inside made me almost physically sick. The entire tank interior was absolutely covered with a fine grayish brown powder with a few larger particles. I spent a couple of hours scrubbing out the tank with hot soapy water and a rag. After drying the tank with a towel and airing it out in the hot sun for a few days, I re-installed it, plumbed everything up, and tentatively poured 5 gallons of fresh fuel from a better gas station using brand new plastic cans and a Mr. Funnel. More flushing and sampling cleared up any residual debris in the lines. Carb bowls and gascolator were also checked repeatedly and cleared up completely.

The takeaway from this harrowing experience:
1. Buy clean fuel from a source that sells a good volume.
2. Use only clean non-metallic fuel cans.
3. Run EVERYTHING through a Mr. Filter or equivalent.
4. Sample your Gascolator before EVERY flight.

[Handclutch]

How do you do you get the funnel to work with the angled filler opening?

Jack

[Tacco]

Jack, As you no doubt know, it?s a pain. I broke down and bought a Flo-Fast pump. Works great. I have had some debris in my gascolator and the only possible sources were the pump and the electronic fuel pump which I recently replaced. I have convinced myself the electronic pump was the culprit. Should have flushed it out before installation.

[tomkk]

Originally Posted by Handclutch

How do you do you get the funnel to work with the angled filler opening?

Jack

I use the Mr Funnel when I put the fuel into the Flo-Fast pump then just use FF hose to transfer to the tank.

[Catbird]

This may seem a bit contrived, but I?ve tied a long string to the tab on the top edge of the Mr. Funnel. I place the funnel in the filler neck and then pull the string over the top of the fuselage and down to the trailing edge of the right-hand wing. Wrap the string around the control tube at the base of the flaperon, tie a simple taut-line hitch, and pull it snug. This Rube Goldberg approach holds the funnel in a secure, almost upright position to facilitate refueling.

[Handclutch]

Thanks for the explanation - a clever way to solve the problem.

Jack

[cajunwings]

Every 24 months I like to take out the wing quick drains out of my planes and let 1-2 gallons of fuel flow into a clean 5 gal bucket. This higher rate of flow can move contaminates that the little squirt into the fuel sample cup will not. I almost always get some grit or water droplets that never show up in the strainer or sample cup. Ymmv and all fuel handling precautions apply.

Don Broussard
RV9 Rebuild in Progress
57 Pacer

[RFSchaller]

I?ve been flying GA since 1985 and only encountered fuel contamination twice. Once coming out of the pump at an FBO and once when some lineman decided it was a good idea to fuel the plane in a torrential downpour on an overnight stay. I actually drew THREE sampler tubes of water out before I got fuel. It was so clear (pure water) that if AVGAS WASN?t blue I might have missed it.

[Catbird]

The challenge for us RV-12 drivers is that, for the most part, we aren't running avgas. Many of us are running down to our favorite gas station and filling up 5-gallon cans at the pump. If you live out in a rural area, such as North Georgia in my case, you can't assume the gasoline is fresh and clean.