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Skyhook
07-10-2006, 12:23 PM
Say you have 20 gal of avgas stored in a dry place for several months. What are the chances of that fuel degrading to point of uselessness- something you'd not put into your plane?

N941WR
07-21-2006, 11:11 AM
This might be a bit late and I don't have any articles to back it up, maybe George can find one.

I seem to remember a few yeas back either the EAA or AOPA magazines had an article about fuel storage. It stated the shelf life of mogas was one year and avgas was two. However, all I could find in a quick Google search was half those numbers, one year for avgas and six months for mogas.

Jekyll
07-21-2006, 11:33 AM
Think of all those airplanes you see sitting at airports. I bet many of them fly only every other month. I don't see them draining and tossing the fuel before each flight and their tanks are open to ambient air. I'd use it with no concern, but that's me.

If you are concerned, mix it 50/50 with fresh fuel and fly.

Jekyll

johngoodman
07-21-2006, 03:30 PM
Think of all those airplanes you see sitting at airports. I bet many of them fly only every other month. I don't see them draining and tossing the fuel before each flight and their tanks are open to ambient air. I'd use it with no concern, but that's me.

If you are concerned, mix it 50/50 with fresh fuel and fly.

Jekyll

I would definitely NOT recommend that. About seven years ago I had a Bayliner with twin 350s and I Wintered it over with full tanks (recommended). It ran fine. After burning less than half of the gas, I filled up at a state run marina and took off. I got about 10 miles before both quit. I was able to motor on one that would still run below 1000rpm to a safe harbor. Changed everything but the fuel. Finally had a mechanic get on with a spare can of new gas. He got in the open engine bay and swapped the fuel sources as I did fast runs. At less than 50% mix, it ruined a pair of full tanks. Had to pay to get 180 gallons offloaded just because of 47 gallons of bad gas.
It's either good gas or bad gas. Mixing will not solve the problem, except ruin more gas.
John

Skyhook
07-22-2006, 05:13 PM
Well, the question is sort of moot, now. I drained the tanks a tiny bit looking for water- there was none. Then I started and ran the engine for several minutes to warm the oil. THEN, I taxied out and took off.

Since I had been flying a PT-17, the -4 seemed rocket-powered and after burning off 1/2 of the fuel I added to full @ $4.48/gal.

There seemed to be no degradation whatever in the performance from that old fuel. Lucky? Maybe.

gmcjetpilot
07-23-2006, 07:33 AM
Can't disagree or agree. Sounds like good advice above. Hey it's 20 gal of gas and (only) 3 months and the better part of $100, but if there is any chance it is compromised (I am thinking more from contaminates) than don't use it obvioulsy, money aside, safety first. You can use it in your lawn mower or any engine that can use leaded fuel. Of course your car is out of the question unless it is a 1960's something. Not saying you should not or can't, it probably is fine, just be careful.

I have heard of fuel getting "stale" but don't have any data on that. Just use a good filters if YOU do decide to pour it back into your RV. I don't think the potency over 3 months is a big issue. Make sure the filter material is suitable and does not become a contaminate itself. They make a dedicate filter for aircraft use. http://www.aircraftspruce.com/catalog/eppages/mrfunnel.php

CraigH@KRPH
07-23-2006, 10:01 AM
Plenty of info on the shelf life of 100LL in this this General Aviation News article. (http://www.generalaviationnews.com/editorial/articledetail.lasso?-token.key=12410&-token.src=column&-nothing) Short answer is 1 year.

Skyhook
07-28-2006, 04:57 PM
Plenty of info on the shelf life of 100LL in this this General Aviation News article. (http://www.generalaviationnews.com/editorial/articledetail.lasso?-token.key=12410&-token.src=column&-nothing) Short answer is 1 year.

Good article; thanks.