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"Old" fuel

Old 04-04-2003, 08:10 PM
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BillHarris
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Default "Old" fuel

I'm not a tightwad, but as a packrat, I hate to throw anything away...

I got involved in sailplanes for a while and now I'm getting back into my power planes. I have two gallon jugs of Morgan Omega 10% and 15%, both about 1/2 full. The fuel has stored inside the house under "cool and dry" conditions and is 4-5 years old.

Should I toss this old fuel and buy some new fuel or can I get by with using the fuel I have on hand? I've run it in an OS 15 FP and a TT 46 Pro and it seems to "work OK".

I plan to get a plane with a TT 91 four-stroke in the air soon. I'm thinking about fortifying the 17% oil by adding 3-4 ounces/gallon of Sig castor oil I have on hand. Yea or Nay?

Thanks,
Old 04-04-2003, 09:50 PM
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jjmiller1
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Default "Old" fuel

Why not. The problem you might have with old fuel would most likely be an obvious performance problem due to the fuel holding excess moisture (alcohol does that if i get's the chance). If your engines run fine on the fuel, I'd say "Use it up". As for adding 3 or 4 ounces of castor, I add 3.5 to every gallon of Omega I buy to get that oil percentage to 20%. That gives me a little more protection in the event of that accidental lean run, and a little more bearing, piston/liner life in the long run. I'm not too familiar with four-strokers though.

If it ain't broke, let me have a shot at it..

JJ
Old 04-05-2003, 11:48 AM
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bob_nj
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Default I Agree

To my knowledge though, 4 strokes may not like the extra oil. Gums up the works!
Old 04-05-2003, 02:14 PM
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Homebrewer
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Default "Old" fuel

The only way to find out for sure is to run it in your engine. Fuel that is contaminated with water will not idle properly but run fine at higher throttle settings (transition may be affected). I think you'll be ok. What matter's most is not how long it has been stored but how long the fuel CAP has been left off and exposed to air.

Just last week, I accidently left the cap off of a fresh gallon of Coolpower overnight. It was extremely humid in my garage and I was concerned the fuel was bad. It ran fine but to play it safe, I mixed it 50/50 with some fresher fuel.

Since you are using Omega which contains 30% castor, I would not add any add anymore than 1-2 oz of synthetic oil to each gallon. I personally think Omega contains too much castor for use in a 4 stroke but is perfect for most 2 strokes.

If you were using Coolpower, 100% synthetic, 2-4 oz of oil wouldn't hurt in my opinion.
Old 04-05-2003, 03:17 PM
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mscic-RCU
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Default "Old" fuel

If it runs in the engine ok, use it. I just recently opened a gallon of 10% from my fuel cellar, probably two to three years old and it runs fine.
Old 04-06-2003, 02:00 AM
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downunder-RCU
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Default "Old" fuel

Some time ago I deliberately added water to my fuel (not the whole can, just what was in the tank) so I could find out what it does and be able to recognise the problem later. Up to a certain point it made no difference. The engine still started first flick and ran exactly the same as with fresh fuel. The "certain point" came at 4% water when it forced the oil out of solution and it promptly settled at the bottom of the tank. It's hard to get an engine to run on 100% oil
Old 04-07-2003, 02:03 PM
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BillHarris
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Default "Old" fuel

Thanks, folks, the fuel runs fine and I'll use it up in my 2-strokes.

Points well-taken on using the fuel in my four-stroke engines, though. The authoritative advice is that excessive castor oil gums up the workin's in a four stroke, so I'll get some "four stroke" fuel.

Remember, I've been away from power planes for a while, and back when, the "usual advice" was that the wasn't really much difference between 2- and 4-stroke fuel, and you could always add oil. The 4-stroke engines I'll be flying this year are a TT 91, a Saito 90 and an OS 120 Twin, so I'd better take care of them.

I can change with the times...
Old 04-07-2003, 08:06 PM
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Default Contaminated fuel

My experience has been that when fuel becomes water contaminated, it may operate ok in one engine but not in all engines.

A case in point is that a member left a half jug of Omege 10 % fuel in the shed at our field after he found that his engine running problems were due to this fuel. This fuel had a murky appearance when compared to a jug of new fuel.

About a year later I arrived at the field one day and found I had forgotten my fuel. Remembering the discarded fuel I decided to try a tankful in my OS 52 FS and found that it ran fine. Next day I tried some in my OS 120 FS and it too ran fine. It also ran well in my OS 45 FSR two stroke, but when tried in my OS 61 FS four stroke it ran noticeably hotter and would not needle properly. In the air it would quit as soon as a power reduction was made after takeoff. Changing back to my homebrew fuel immediately cured the problem.
Old 04-12-2003, 12:53 AM
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dpsper
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Default "Old" fuel

Hey if your not comfy running it at least you got a lifetime supply of weed killer to keep your sidewalk or other areas looking nice.
Old 04-21-2003, 09:37 PM
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Basil Yousif
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Default "Old" fuel

I have a thunder tiger 91 four stroke and Power Master 15%nitro
fuel with 18% Snth/castor oil mix. Does this need 2 or 4 oz of castor oil to be added to reach 20% when braking it in. If not
what do I use for a synthetic oil instead of castor. Also If I use castor oil can I use the 4oz bottle at longs drugs (laxative) to add
or is this not degummed. That's the only source of castor I can find.
Also when making after-run oil can I use Automatic transmission Fluid and MM Marvel air tool oil in a 50-50 mix for the four stroke and my 2 strokes.
Old 04-21-2003, 09:51 PM
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CHassan
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Default "Old" fuel

I just finished off a 1/2 a jug that was about 1/ 1/2 years old, and I am working on a second 1/2 of a jug that is over 2 years old. Not a problem running with either.
Old 07-24-2003, 03:26 PM
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SpaceCase
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Default "Old" fuel

I'v got four gallons of tower heli fuel that are ten years old. Its kinda like wine, no? I'v heard you can add a small, few capfulls, of aceatone to help the fuel resist the take up of water, this may not help me now. My other concern is the nitro, I know that evaporates and now I mostlikely have ama fuel now. I also have a saito four stroke i was thinking of useijng. hummmmm
Old 07-24-2003, 04:52 PM
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Basil Yousif
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Default "Old" fuel

I had a gallon of Power Master Fuel that I used up over 5 years and it got pretty water logged at the end of the five years so I used the rest for cleaning the outside of my engines. I think the biggest key to keeping the fuel good is how well it is sealed. I opened the bottle and used it over many years with air getting to it and moisture getting in it. If these gallons were not opened and no air got in they should be good. You can easily tell by the performance of the engine if the fuel has moisture in it, the engine will quit all the time or run rough and no adjustments will help will help the problem. Also getting the engine to a smooth low idle is almost impossible. If you do use the gas pump alot of after-run oil into it afterwards. The cheap formula for after-run oil is 1/2 ATF oil , 1/2 Marvel Air Tool oil - Mix.
Old 07-24-2003, 08:27 PM
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SpaceCase
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Default "Old" fuel

Dry gas? Can I add dry gas to this to make the h2o come out?
Old 08-06-2003, 06:51 AM
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w8ye
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Default "Old" fuel

Dry gas is just ethanol (sometimes, it may have isopropal or methanol in it too.) so that the water present in the bottom of a gasoline tank will go into solution with all the rest of the gas and go on through your engine. The water will mix with the ethanol and in turn the ethanol will mix with gasoline.

In glow fuel, it's methanol based. The problem is with the water being absorbed into the methanol. It causes the lube to become unstable among other problems. The engine will be impossable to needle at lower speeds and be unstable at higher speeds.

To use dry gas is rather pointless in glow fuel.

Enjoy,

Jim

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