Mohney

I have a jug of fuel that is about 1 year old. Is it safe to use? How do you tell if it is too old?

Also, I have been reading that after run oil is the same as automatic transmission oil?

bkdavy

My Feedback: (1)

Safe to use and effective are two different things. If the jug has been factory sealed, and sitting in a location away from sunlight, the jug should be fine. If its been opened, how much fuel is left in it? If it nearly full, closed, and in a dark location, you should be good to go. Nitromethane will break down in sunlight over time, so you might see some degradation in performance. If its been open to air, the methanol will absorb some water, and some purists believe that will be a problem, but your average Saturday flyer probably won't notice the difference. It takes a whole lotta water before you really see any significant difference.

As for after run oil, you'll find differing opinions. I use Omega 10 and Omega 15, and they specifically recommend not using after run oil. I haven't, and haven't had any problems with corrosion. I always run the fuel residues out of the engines, keep the throttles closed in storage, and clock the propellor to the compression point to keep the exhaust sealed. There's usually plenty of oil left in the engine from the fuel.

Is ATF the same? Not necessarily. Many people use it, but there are different types. I've heard of people using Marvel Mystery Oil. I tried it once when I was a beginner, and I wasn't happy with my glow plug performance afterward. Do a search on ATF, and you'll find lots of information in other postings. Make sure you search the Glow engines forum as well. There was a recent posting about ATF (something about debunking the myth).

Brad

Mohney

Thanks Brad. The gal jug has been stored in my basement and about half full. I will try your suggestions on postings.

da Rock

There's a slight problem here.... but more on that in a second.......

Fuel is light sensitive. If it was stored in the dark (opaque jug or where the lights are off most of the time) there's no problem.

But unopened factory containers can still not be sealed. I had 4 gallons of unopened fuel stored for a number of years. One gallon leaked out. One gallon evaporated about 10% of it's volume out. The other two showed no change in volume. But that's no problem because you can see exactly what you've got. (One lost gallon and one unreliable gallon)

Fuel can actually do two bad things in storage. The nitro and propolene oxide (and other igniters etc) can evaporate off if the container isn't good and tight. You'll see some volume change here. And just losing the nitro isn't much of a problem. That fuel can be salvaged if you mix it with other good fuel (when you really need the nitro for certain engines). And the fuel can absorb water. Alcohol sucks it in, given the chance. So...... It's possible to make a good guess, if your fuel has lost it's nitro or if it's not sucked in some water, by looking at the volume, IF you knew what the volume was to begin with. If the volume hasn't changed from full, the fuel is safe to try out. If the volume has changed, I'd really think hard about using it. How much did you pay for that engine?

BTW, if you're going to test fuel to see if it's "still working" you really ought to fly a tank of good fuel first. Then you know that you've got a good needle setting on your engine when you try out the old fuel. If the old doesn't hold the same needle on the ground, think hard about it. Give it the pinch test and if it doesn't do exactly what the good fuel did, think hard. After the good fuel flight, turn the prop over by hand. How does it feel? Nice and free? What's the compression like? Remember those. So now, run the old stuff and if it does seem ok on the ground, fly a couple of circuits and even if it seems to be flying just as rich or good, land it, shut it off, and turn the prop over by hand. Still feel the same??? kewl......

At the field, I recently was called over because a "previously great running" engine wasn't pulling good anymore and had shut off in flight a couple of times and "it never did that before". Turns out the guy was burning off some fairly old fuel. I didn't have the luxury of having felt how the prop turned over by hand before that old fuel run, but now it was really not free for sure. I flushed the tank and filled it with some of my fuel. Shot some in the nose and turned it over 10 or 20 times by hand and it started to feel free'er. I cranked it and shut it off. It wasn't perfectly free but was some free'er, so I set it slightly rich and told the guy to give it a shot. He was pleased, but after that flight I felt it again and it felt to me like an "older" engine. It was free now. But it's compression wasn't new, for sure. I don't know what it's compression had been before the old fuel, btw. Old fuel ain't a bargain.

w8ye

My Feedback: (16)

My experience with "Bad" fuel is that it doesn't run consistently. Will likely shut off on you. When really bad, it will not run without the glow ignitor hooked up.

I've had more bad experience with sunlight than anything.

Enjoy,

Jim

MinnFlyer

My Feedback: (4)

Hang on to it and try it next season. If you experience any problems with it, set it aside and use it for breaking an engine in, or just keep it around the shop for lubing up a stuck engine, or whatever else you may need a little fuel for.

Mohney

Wow! All great suggestions. This really helps. Sounds like it is bad since my engine will not run without the glow plug ignitor.

Thanks!

Jim Thomerson

I have a third of a gallon of Red Max 5% nitro which got lost in my basement about 25 years ago. I run a tankful through something on the bench from time to time. Seems to run OK. I don't have any use for it as a flying fuel. If you have fuel which has a leaking cap, I would bet your major problem is methanol evaporation. Methanol evaporation is faster than water absorption in fuel . So your old fuel may have a high percentage of oil compared to what it started out with. That might explain how it runs.

w8ye

My Feedback: (16)

Old glow fuel makes great bug repellent, suntan lotion, spray around the house for insect killer, and makes great weed killer.

We've been pouring it on the fire ant beds at the flying field.

I have used it to break in engines. Just leave the glow ignitor connected and run at moderate speed.

Enjoy,

Jim

Mohney

Jim,

Thanks for the suggestion on putting around the house! I will try it on my problem ants! Probably better than the Orkin man! Ha ha!

Eric

bruce88123

Be sure it isn't just a bad plug.

Mohney

bruce88123,
Nope, replaced glow plug and still does it.
Thanks.

britbrat

Yup.

fireplug1111

My Feedback: (21)

MOHNEY:

Two things 1st the easy one. After Run Oil is a waste of money. My latest edition of AMA video put out by the AMA says WD40 a couple of short squirts in the carb and let it set.
2nd..... Old fuel. Let me tell you a story. Glow fuel has nitroglycerin in it. Nitro does not evaproate. Back in the older days fuel used to come in metal cans. the reason it does not anymore is that fuel can get old -- years old -- and then nothing but nitro left. Metal cans that are unscrewed can cause minute friction and friction and nitro does not mix. Just as the guy who now does not have any arms. He lost them from this very reason. If its older than a year its gone. $13.00 isnt anything to mess with.

bkdavy

My Feedback: (1)

Just to maintain accuracy, glow fuel has Nitromethane, not nitroglycerin.

Brad

flyinrog

My Feedback: (1)

I have a 12 year old gallon in the basement and its been a couple of years but I have run it in test engines....Rog

britbrat

That's quite a story -- but it is just that -- a story.

Very old glow fuel may, or may not be particularly effective in your engine (probably will be just fine, unless it has been left loosely capped), but it will not be any more unsafe than new fuel.

I have used glow fuel that is several years old, having been kept sealed & in its bottles & in the packing case. It worked just like stuff fresh from the hobby shop. I also use fuel that is left over from the previous summer -- it stays in my garage in its tightly closed poly-bottle & is subjected to sub-zero temps. It works perfectly well in the spring.

I use really wet (water contaminated) old fuel for breaking in engines on the test bench -- just leave the glo-driver on (if necessary). The engines love it.

What can be unsafe is old model diesel fuel -- it contains ether & can have oxidized ether residues (peroxides) on the screw cap -- nasty stuff. Maybe the guy in the story opened an old can of diesel fuel.

Jim Thomerson

AMA video suggesting a couple of squirts of WD-40 instead of after run oil?[:'(]

Balsa Master

did a test, i have a bottle of norvel 10% out in the garage thats over a year old (pushing 2) its been sitting on a shelf so its been in some sunlight, but not direct and it managed to keep my big mig .61 going. i didnt keep it runing long so i dont no how reliable the fule was, but it did burn.

downunder

As has been pointed out, glow fuel has nitromethane. But the original story was supposedly about diesel fuel where the ether slowly crept out past the metal lid but in so doing formed some kind of crystals which were shock sensitive. I have my doubts about the story but who knows?

Balsa Master

nitroglycerine C3H5N3O9
nitromethane CH3NO2

good luck getting nitromethan to break down into somthing with more potential energy stored it in....