Running on Mogas

[BritishCubBloke]

What comments do people have on the issues raised by wyrmio in this detailed posting (seventh down in the thread) about using mogas:

http://www.pprune.org/forums/showthread.php?s=&threadid=69425

I'm certainly interested in it for my 150 with an O320-A2B. All thoughts appreciated.

BCB

[StewartB]

I have asked a couple of different engine shops about this, and they say the cost savings at the pump isn't worth the damage you're doing inside the engine. I talk to guys that run auto gas that say they don't have any problems. Who is right? The last time I filled my truck tank avgas was only about 25 cents more than car unleaded, so I use avgas and avoid the uncertainty. As for the comments made in the thread, I haven't seen a bunch of planes falling out of the sky from car gas use. And, if people were dying from it's use, our AD-happy FAA would surely jump on the opportunity to prohibit it.

[SuperCub MD]

I did some back to back real world testing with mo-gas and 100LL. No difference at all. With mo-gas, buy it and burn it, it does not store as long, and never keep it from one season to the other. Around here, the price difference is close to, and sometimes more than a buck a gallon, which adds up real fast.

I've never personnaly seen any engine damage that could be attributed to mo-gas. Using it will void the warenty on most overhauled or new engines, but the warenties useually run out fast anyway.

I have seen vapor lock problems on tightly cowled aircraft, but not a 150 Cub.

[BritishCubBloke]

The difference in the UK would be $4.20 a gallon as opposed to $5.50 or more. Flying is an expensive business here.

What about vapour lock at altitude? That seems to be what everyone worries about.

BCB

[SuperCub MD]

I'm afraid of hights, so can't comment there. My altimeters are always sticking from lack of exercise. Buy the cheap gas and stay low and slow.

If I had to operate at high altitude or very hot climates, I would be careful with mo-gas, but do not operate in either, someone else may have experience with this?

[Steve Pierce]

Hot summer days in Texas (100 +) I've seen a Cherokee 160hp and a Cessna 182, and a 172 get vapor lock. Drained the fuel out put 100LL in and they ran fine. I use it from time to time and never have a problem. My dad has 150hp Clipper and runs Mogas all the time except for break in and has never had a problem. You need the lead for the valves on break-in.

Steve

[T.J.]

delete

[Stan]

I've been burning Mogas for the past two years. 1975 SuperCub with O320-A2B in E. Tennessee. Utilize a 55 gal tank and pump in back of pickup truck for supply. Gas station just two miles from the hangar. Filling often eliminates moisture and stale fuel. I fly an average of 200 hours per year so my fuel doesn't get old. Top off with 100LL when I land at other airports as a courtesy or if I'm in need of fuel. Haven't experienced any problems.

[SuperCub MD]

One thing I forgot, some will run 100LL in the left tank and mo-gas in the right. Take off and land on the left, and run the right in cruise. This eliminates their worries, and leaves 100LL sitting in the fuel system when parked, and eliminates the bad shut down/startup problems of mo-gas.

[Carl]

You don't want to leave mogas sit very long, they put a lot of crap in it they cann't dump anywhere else, also water in suspension. this stuff comes out of suspension in a short time.
Engines more prone to carb ice ( especially continentals ), also sometimes you get a little run on after shut down
Probably about 50 Beavers in the Bristol Bay area that run nothing but auto fuel. Everyone tht runs floats in that area buys fuel and hauls it from Moody's Oil on Lake Aleknakek. They use av for 185 & 206s, but mogas for everything else. Thousands of hours flown every year, and no problems associated with fuel.
We used to use auto fuel in the 185s if we couldn't get enouf av. Fill on tank with av and the other with auto, then take-of and climb on the av tank, and switch to both at cruise.
If you mix av with mo 1-3, you increase the octane of the mogas approx 8 points, due to the octane boosting property of the lead, thats why it was put in fuel in the first place ( the ability to use softer material for the valve seats was a byproduct). By mixing you boost the octaine enough to use in the engines rated for 91 oct like the O360 and the IO470
Carl

[PA12driver]

I ran an 85hp Continental in a T-craft for 1500hrs on Mo-gas no problems (except I did have to watch for carb Ice more often) I had the EAA STC for car gas for my 64 cub and 79 cub both with 0320A2B they both ran fine (they did run a little rich at low RPM) I ran the 79 to TBO without even doing a Top end job! I would be somewhat concerned about the gas stations switching to Alcohol additives (they do around here), I don't know if they have to tell you or not?

I have noticed that If 100LL sits in the sun in 5 gallon cans the blue dye will seperate and the stuff looks just like car gas (except for the lousy smell!)

In Canada they dye Marine gas so they can catch folks that use it in there car? They tax more for car gas!! or the other way around?

What are you all paying for 92 octane auto gas versus 100LL. Around here the best price is $1.31 for auto and $2.00 for Av gas?

Tim