What is your experience using automotive gas in airplanes?

I fly a 601XL with a Jabiru 3300 engine. The other day I ran into an old-time pilot who has been using automotive gas in his airplane for many years. He reports no problems, in fact he had only good things to say – like longer engine life since he switched. Jabiru does permit the use of premium auto gas in the 3300. I am contemplating the switch for the following reasons:

1) Longer sparkplug life. I have gotten 170 hours out of my last two sets of spark plugs which is hours 70 more then Jabiru calls for. Last time I changed them I installed iridium plugs which I expect to last the life of the engine – unless they get too fouled up with lead to work that is. The last plugs I pulled had very significant lead deposits on them.
2) Reduced air pollution. The engine does not need the lead. Why spew it into the air then?
3) Less muck on the bottom of the plane? Even though I have exhaust pipe extenders, the underside of the airplane is impossible to keep clean. I suspect most of this is not lead but still, when I am under there on my creeper scrubbing the stuff off I wonder what is in the goo that runs down my arms.
4) Reduced cost. My plane has about 430 hours on it. If I had been burning auto gas instead of 100LL I would have saved about $4,000 dollars on fuel over the past 2 years – wow that’s not small change.

On the down side hauling up to 30 gallons of auto fuel to the airport in my car seems like a pain and possible safety issue. I have been contemplating using existing gas tank in my car for transport and use a purpose-built 12 volt electric fuel transfer pump to move the fuel – I see them on-line for about $140. I don’t tend to land my plane with the tanks completely empty – I hear it’s a bad idea – so chances are my car’s tank would almost have the fuel I need to fill the plane.

On cross countries I would revert to using 100 LL since automotive gas at airports is hard to find.

I would love to hear from those who use auto gas in their planes to learn your experiences and tricks to make this as painless as possible.

Thanks, Steve

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Comment by Thomas Richardson on April 2, 2009 at 3:38pm
Zenith factory planes succesfully run on only 100LL. Both the 80HP and the 100HP. I attended a seminar at Sebring by Phil Lockwood who is an authorized Rotax repair and sales center and he said 100LL is no problem other than as you stated , more frequent oil changes and the use of a high grade motorcycle which he recommends whichever fuel you use. I would be curious to know if your state has mandated 10% ethanol as Florida has. This seems to be a real problem for aviation boating , and as I just found out Lexus is doing major recalls on their cars in Florida because of the alchohol related issues of fuel system parts being eaten up.
Comment by Stephen R. Smith on April 2, 2009 at 3:36pm
Bob,

Thanks for that information. I did not know that Rotax advises against 100LL nor did I know what the dangers are for that engine.

Do you haul you own fuel to the airport? If so, what have you worked out to make that quick and easy?

Steve
Comment by Bob Jones on April 2, 2009 at 3:08pm
Steve, anyone using a rotax should be made aware that the only fuel to use , except in emergency or limited use is Auto fuel, rotax cautions the use of 100LL and requires more frequent oil change if unavoidable, due to a very good reason, if a oil is not used that is formulated to keep the lead in suspension, the lead drops out and coats the reduction gears, decreasing the tooth clearance, and could split the gear case or at least cause extra wear, I personally have to date run 1,935 gallons of premium unleaded fuel thru my 912s and it still showed 79/80 on the annual and runs Perfect ...BOB
Comment by Stephen R. Smith on April 2, 2009 at 2:18pm
Taylor,

Thanks for that excellent post. I like your conclusion: Fly often.

I have had auto gas gum up lawnmowers and weed-whackers so no doubt that can happen in an airplane.

What do you think of the idea of turning the fuel off and running the engine until it quits? That should get most of the fuel out of the carb. By experimenting I think I could learn to turn off the fuel while taxiing in, then sit in front of the hanger and run till it quits. On the Jabiru 3300 I could turn on the choke as the level in the float gets low and the engine leans out. That would keep it running till the float is empty, I think.

Steve

Steve

Steve
Comment by Taylor Ogden on April 2, 2009 at 12:47pm
I've been running auto gas in my 150 for a year, but took a 6 month hiatus this winter and got a bit of a shock when I went to run it again.
The auto fuel available nowadays does not have preservatives (why would they go to the expense since they can't make gas fast enough for our consumption?) and the fuel gummed up the mixture cup in the carb. Had to replace the mixture actuator as it slipped on the rod and wouldn't operate properly. That cost 100 bucks.

It also gummed up my fuel strainer and I had to disassemble and clean it all out to get it to work.

As for actual operation, I love it. The O200A runs great and the plugs were nice and clean. Starts after one blade passes. I'll continue to run auto gas, but will switch to 100LL in the winter or any time I expect to take some time off from flying.

The moral of the story is: Fly often to keep your gas fresh. It's a win-win!

Taylor
Comment by Stephen R. Smith on April 1, 2009 at 10:28pm
Jim, thanks for your input. I am hoping the rubber parts supplied by Jabiru will be ok with the alcohol in our auto gas here in California. They only offer the caution that vapor lock is more likely and they suggest cooling the fuel pump which will be easy to do. I just need to tap into the system I have in place to cool the mags. I also have heard that water problems are more prevalent with fuel containing alcohol.
Comment by Jim Belcher on April 1, 2009 at 11:55am
I ran auto gas in a Tri-Pacer with an STC a number of years ago. The engine ran fine, and ran better than it ever did on 100LL. It ran about the same as it did running 80 octane avgas.

However, the audo gas dissolved seals in the fuel system about as fast as I could replace them. I reluctantly had to quit using auto gas because of the seal problem. I would check samples of any seals (hose, o-rings, etc etc) in a jar with a fuel sample before trying to actually run auto gas in my airplane.

I hear bad things about burning auto gas with alcohol in it, but having not tried it, I can't comment.

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