Marinating with Auto Gas....

First, I hate to admit to being a "Lurker" for so long(a year) but the stuff on this site is really amazing. Priceless amounts of information and experience....love it.

The Question...
I have a friend who has let his '46 PA-12 sit in a hangar for way too long. Finally, after probably a year of not flying(only being run once in a while on the ground which isn't much better) it is flying again. Though not much was done, besides an oil change and a thorough run up. It has had Auto gas in it all this time, and I have read a little about the pro's and con's of using auto, but don't know much about what to look for after sitting for so long with it in the tanks/lines/ carb etc... Before it really starts flying there is a list of items that need to be taken care of(well, ok, annual....) But specifically, what could we look for/inspect/replace just due to the poor storage qualities of Mogas.....any unfortunate occurences of lessons learned the hard way after something similar to this situation?

I have heard to start with the carb...

Thanks a lot...
Philip

Auto gas...sitting for a year.

Due to my own experiences, I don't think I would take it far out of the pattern for a while....check the cam lobes for pitting when you have a cylinder off, put Marvel oil in the oil and gas, run it hard and often, and watch like a hawk for increased oil consumption, signifying cylinder glazing and ring seating(not) due to the black goo around the piston rings (oil, carbon, gas, and lacquer) hardening from disuse. I'd be much more worried about corrosion in the engine from disuse than it being 'exposed' to autogas. Any lacquer formed from stagnant gas will be cleaned out (eventually) by the MMO. Check with your IA to do a corrosion check on the engine and airframe. You live in a 'rusty' part of the country. p.s. Don't believe anything that I say....I'm not an IA...

I'm no IA either, but I'd be inclined to drain the gas and start fresh if it's the same autogas that's been in the tank for a year. I sure wouldn't put any supposed cleaning additives into old gas and then run it into my carb.

The starting up regularly does help by redepositing the rust preventing film some, but it rarely helps prevent the acid or sludge forming in oil.
If the oil that was in the engine for that year had a lot of hours on it, I personally would plan on changing the oil again at a really short interval after flying it.

If I were real cautious, I might consider pulling the carb and having an accessory shop check it for buildup and damage from the car gas additives.

If the autogas had ethanol in it, I'd be inclined to look for corrosion. Find someplace that was low enough to collect and look in the bottom. I personally don't believe all of the manufacturers scare tactics regarding autogas, but I believe them enough that I wouldn't consider storing it in the plane. One really big difference (and this one I actually know a little about) is the volatility. Autogas has very few (none in cheap gas) stabilizers for volatility. 100LL does have stabilizers. Autogas typically starts out with much higher volatility, but it could conceivably end up lower after a nice hot summer.

All just opinions...
KL

I would drain the carb bowl and catch the contents. I would also drain the entire system and put in fresh gas. Check and clean the gascolator. Check the oil pressure screen and the suction screen. You might do an oil analysis to get a base line and another in 25 hrs. or so. Keep checking the screens and check your static rpm. If the cam is going it will show up in a decrease in power and making metal. I have found corroded cams and lifters that only showed up in an oil analysis. They weren't real bad but on their way. MMO in the oil and gas will help lubricate the top end and loosen up the rings.

I would bore scope the cylinders (each one ) to see if there is a rust ring or pitting . I had an engine failure in a Citabria w/ an 0-320 after almost 50 hrs of flyings because it had sat for several years and only had the engine turned over once in a while. It developed a rust ring in each cylinder that caused the wrist pin caps to disintegrate with a engine failure not far behind.
Auto gas use in that engine is ok but not for storage. Problems can occur in your lawn mower over the winter. I have been flying a SC with auto gas for over 4 years now with no problems just keep the stuff fresh.

Philip, bring that thing down here we'll put some time on it. :lol:

ya know...

When I get this figured out I might just have to take you up on that Tim......
(The guys @ Pomona might actually let me stay this time with the wheel on the proper end of the airplane.)

-Philip

Possible alage or other crud in gas tanks

I have been getting some algae-like looking stuff when I sump the tanks, some days more than others.. brownish blobs that tend to sink in the fuel. we thought it would go away after a few tank fulls but it hasn't. I bought the plane 4 months ago and don't really know what was in the tank before, i'm guessing some auto gas for sure. I have completely drained the tanks a few times, pulled the quick drains out, ran some fuel through.. Question is what to do about it, keep sumping, or do I need to add a biocide, or have the tanks taken out and something more serious done to them?

I hope someone did not put tank sealer in those tanks. As I recall car gas softens Randolph tank sealer, I would be real fussy about cleaning the entire system. Jim

Auto Gas.....

In the low compression aircraft engines, auto gas works fine, and keeps your plugs very clean, but storing a plane with auto gas may develop problems. As auto gas becomes old, some part of it changes, and even though it does run, it may not run well. My #1 son left his Cessna 150 tied down outside for a couple of years without much attention, and he pulled the fuel tanks and cleaned them out when he wanted to get it back going. I put some of the old gas in, 1) a lawn mower, and 2) in a Jeep. The mower ran ok, but the Jeep pinged like crazy. Some engines will function ok with old auto gas, but others do not. My advice is to drain the fuel, and carefully inspect the entire fuel system. If your friends engine had any latent moisture in it when he shut it down before the long period of non-use, I would want to look at as much of it as possible. When the big fan stops turning, its really quiet, except for your heart beat.

Mike

Setting

I'd fire it up, let it idle for a minute, slam the throttle forward and go flying. But then that is just how I do things. Crash

Autogas

Don't forget the winter vs summer formulations of autogas...