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View Full Version : Fuel: AVGAS 100LL !?



Patrik Sweden
05-26-2006, 06:17 PM
Is it anyone who tried running a Mercruiser MPI with fuel 100LL? (for airplanes)

mrfixxall
05-26-2006, 07:04 PM
Its a wayste of money..the boat will run the same as if you had 93 it it and besides i wouldnt run av fuels because it has a ton of additives like fuel antigelling to keep the fuel from freezing at high altitudes etc etc etc...

Patrik Sweden
05-26-2006, 07:09 PM
I know.. but a friend of mine bought 1200 liter of this... and he can't use it! So it's for free!! But I don't know if the engine will like it!?

Fuelcost in Sweden: $ 2/liter

MOP
05-26-2006, 07:17 PM
Patrik there have been several threads on octane, the AV gas will steal power. Do a search there is some good info.

Phil

Patrik Sweden
05-26-2006, 07:31 PM
yeah, I know.. but this is not a question about octane, I was woundering if anyone has driven their boat with this kind of fuel. Some say that it's containing Acetone... Will it harm the engine?

edit: I can't find anythin on AV gas..

MOP
05-26-2006, 08:56 PM
yeah, I know.. but this is not a question about octane, I was woundering if anyone has driven their boat with this kind of fuel. Some say that it's containing Acetone... Will it harm the engine?

edit: I can't find anythin on AV gas..

Acetone will not hurt the engine though I doubt it has any in the AV gas, a few of us tried Acetone in our fuel to improve mileage there was quite a thread. It did add a little but hardly worth the bother, being a fuel is very expensive I would consider mixing it with regular grade to cut the octane down. It would be a shame to let it go to waste, you may be a bit slower but at half the price. Maybe one of the more knowledgeable can give you better guidance.

Acetone thread: http://www.donzi.net/forums/showthread.php?t=38955&highlight=Acetone

Phil

Patrik Sweden
05-27-2006, 12:41 PM
Acetone will not hurt the engine though I doubt it has any in the AV gas, a few of us tried Acetone in our fuel to improve mileage there was quite a thread. It did add a little but hardly worth the bother, being a fuel is very expensive I would consider mixing it with regular grade to cut the octane down. It would be a shame to let it go to waste, you may be a bit slower but at half the price. Maybe one of the more knowledgeable can give you better guidance.
Acetone thread: http://www.donzi.net/forums/showthread.php?t=38955&highlight=Acetone
Phil

Thanks! So you don't think it will hurt my engine?

Chili 18
05-27-2006, 01:55 PM
Free av gas..... Go for it! :yes: Wont help perf. unless you had HI compression.. But wont harm anything.

joel3078
05-27-2006, 02:29 PM
Don't burn the gas in a boat! Create some ads and sell it!!! There has got to be planes in Sweden that would need to burn it. If someone is giving away free aviation gas, you owe them a big hug, kiss, handshake, etc. On the flip side, if it's free, is the gas bad, old, fouled or something like that. Nobody would want questionable gas in an airplane.

DonziJon
05-27-2006, 04:17 PM
100LL Avgas has a very high evaporation rate just like Acetone, but I don't know if it has Acetone in it. I did see a guy a few years ago show up at the airport with a Big Cig looking for gas. John

Avialanche
05-27-2006, 04:27 PM
I'd fill with half & half of regular gas and Av gas, plus i've heard of Cessna's and other piston powered small planes that use regular auto gas as a substitute for AV gas to save on fuel cost, so i guess the fuels interchange both ways, but 100LL might make 454 Mag engine run hotter than normal though plus there's color dye in the AV fuel that might leave deposits in Cylinders and on the Plugs.

Greg
05-27-2006, 07:48 PM
From what I've been told, its not what's in the AV gas that will hurt your engine, but it's what's not in it that will hurt your engine. I don't have any facts to back it up, although the gentleman that told me that owned a fleet of airplanes and a highly modified Vette. Hope this helps.

Patrik Sweden
05-28-2006, 11:19 AM
Thanks guys!

I won't take the risk and fill her up with this.. I will use it for my other engines.. moped, lawnmover and the old 2-stroke outboard..

MOP
05-28-2006, 11:28 AM
All of this just to tell us you now have a 100 years worth of small engine fuel:biggrin.: :biggrin.:

Phil

Patrik Sweden
05-28-2006, 12:42 PM
:biggrin: :biggrin: Yupp!

But if you take the ride over the Atlantic, I will give you the gas for the trip back to US.. AND... I will buy you a couple of beers!

Some say; No problem, fill her up!! Some says: don't do it!.. I have to be sure.. My last BB blow up 6 month ago... so I don't risk anything!

gcarter
05-28-2006, 03:09 PM
Isn't the idea of high octane fuel to allow the use of high C.R.'s w/o detonation?
If so and you're at a "normal" c.r., then you probably would lose power.

oldandtired
05-28-2006, 03:56 PM
The only problem with running the avgas would probably be leading your plugs reulting in misfiring. My internal comustion professor told the class about using it in a hi performance BMW years ago and lead fouling the plugs. If you ran it at 50/50, I doubt you would have a problem.

Rene

The Hedgehog
05-30-2006, 10:58 AM
We have done it a bunch in high performance cars and motorcycles. It works fine. What these guys say about not improving the performance is true. You need a high compression engine and to adjust the timing to see real benefits. You could mix it with lower octane gas and be just fine. If you run it straight you will need some sort of a fuel additive to counteract the antigelling agent that takes out some of the lubrication properties. Teague had an article on it that basically says the same thing. I can't remember what he recommended using as an additive.

I would love to have some free 100LL. I could mix it with 89 and really crank up my boost. That would be big fun.

Patrik Sweden
05-30-2006, 12:51 PM
We have done it a bunch in high performance cars and motorcycles. It works fine. What these guys say about not improving the performance is true. You need a high compression engine and to adjust the timing to see real benefits. You could mix it with lower octane gas and be just fine. If you run it straight you will need some sort of a fuel additive to counteract the antigelling agent that takes out some of the lubrication properties. Teague had an article on it that basically says the same thing. I can't remember what he recommended using as an additive.
I would love to have some free 100LL. I could mix it with 89 and really crank up my boost. That would be big fun.

Thanks! Have you run it on a MPI engine? I'm affraid that it's affecting the "injection system"..

What is: "antigelling agent"
(my english is not the best.. we speak swedish here you know :D )

Patrik Sweden
05-30-2006, 01:05 PM
Another thing...

I got this gas from a friend who bought it to his JetSki's (SeaDoo) and his supercharger didn't feel so good, why did this happend? Is it anyone who could answer that!? That's what I'm afraid of..

Sorry to nag about this...

blackhawk
05-30-2006, 06:02 PM
I don't know anything about AV gas. But running higher octane when you don't need it will produce LESS hp.

If your friend's jet ski is stock then the higher octane produced less heat and made less hp.

DonziJon
05-30-2006, 07:58 PM
Hi Patrik: I did a "Google" of "100LL Avgas" today. You might find some good info in the first 2 pages or so that show up. "AOPA" is THE BIG (GA) General Aviation Support Lobby in the US. General Avaition is NON Commercial...corporate jets and piston engine private. Check other entrys as well. I even found an entry about JetSkees....which are by the way TWO STROKE Engines ...not the same as your inboard Four Stroke. John

EDIT: By the way, someone above mentioned that Some (GA) Aircraft can use "Auto Gas" (called "MoGas" by the GA community) instead of 100 LL. This is true with some older aircraft.. HOWEVER: Modifications to the aircraft ARE required as well as "Certification" by the FAA. It's called an "STC."

The Hedgehog
05-30-2006, 08:14 PM
Thanks! Have you run it on a MPI engine? I'm affraid that it's affecting the "injection system"..
What is: "antigelling agent"
(my english is not the best.. we speak swedish here you know :D )

No, I have not run it on a MPI boat engine. Lots of fuel injected airplane engines though so I don't see an issue there. It is cleaner and much higher quality than auto gas. It is not good when fuel injectors get clogged on a plane. I will try to drop my father a line. He has bound to have run it in one of his fuel injected vehicles.

It is more customary for planes to sit for a while without being run. Avgas has agents in it to prevent it from gelling over time. Once again, it is not good for gas to go bad but it is very bad for avgas to go bad.

BigGrizzly
05-30-2006, 10:04 PM
We have played this game several times. The av gas has among other things Deicers which are confused with alchy. Althoe they should not hurt the injectors they mite hurt the O rings and float in the fuel tank sending unit. The suggestion to sell it was the best. after 30 years racing motorcycles and cars I know av gad belongs in the air only. Years ago a fellow MC racer named Johnny Dupont Jr. (yes the same Dupont paints etc. ) who owned a airport in Wilmington De. came in with av gas. he had a heck of a time and asked for my help. I dumped the gas and put in the lowest union 76 gas at the loval station. his problems were over. Problem is av gzs has a higher vp thAN NORMAL FUEL so ends up in the exhaust un burned. I won't get techee with you guys but every time someone trys this trick it always hurts.