Rotax medium term storage prodedure?

I can't seem to find any information in the Rotax maintenance manual or by doing searches on this forum. I'll be heading south for 4 months and need to store my RV-12 in a hangar until mid April. In the past, I've stored my 182 by putting in Phillips anti corrosion oil and closing off the intake, exhaust and breather. Any suggestions are welcome.

John

John.

My 912 is in a Flight Design CTSW that I have had for 7 years and 350 hours. It is in a well insulated hangar so temperature variations are minor day to day. Actual temp. is dependent on season.

I have left it, usually during winter, for 3 months several times. A couple of times with ethanol free mogas and 100LL mixed 50/50 and several times with Stabil mixed into ethanol free mogas.

I also put blocks under the axles and turn the fuel off to prevent any fuel escaping due to a flat tire or stuck open needle valve problems. Shouldn't be a problem on the low wing -12 with baggage mounted fuel tank. A float charger stays on the battery.

So far, I haven't had any noticeable problems. I suspect that if I were to leave it 6 - 12 months that it would be wise to pickle it properly, what ever that is. Rotax probably has recommendation but I have never seen them nor looked for them.

Thanks Sandpiper,

I'm just north of PDX about 16nm so our environment is much the same, except that my hanger isn't insulated. I'm using 92 OCT non-ethanol mogas but plan to put Stabil in as well and put the battery on a Battery Tender. I also put a 45 watt halogen lamp inside the cockpit to keep it above dew point.

Don't leave the 92 auto fuel in for 4 months even with Stabil. Drain it for that long. Especially dump the carb bowls. Don't let fuel sit in them that long or you may be pulling them and cleaning the idle jet. The hole is so small it gets a film over it easily. I would plug the exhaust and air intake. Put a float charger not a trickle charger on the battery or take it out and do it. When you get home put fresh fuel back in and if the oil has any run time on it change it. The engine would be ready for a start. But if it were me after that time period I would want every thing well lubed for the first start. I would do an oil purge. Not because it needs an oil purge per say, but because you want to make sure every thing that you can coat with oil before the start can be. It's a better safe than sorry approach. I know some will say my lawnmower starts right up after 4+ months storage, but this isn't the lawnmower and should have better care.

Roger, have you had any experience with auto additives designed to keep the carbs clean? I haven't tried them, but I was wondering if there is any experience out there good or bad.

This will be one of those personal choices with no hard and fast answers.



I have used them off and on for many years. There are many of them out there with all kinds of claims.

http://images.search.yahoo.com/search/images?_adv_prop=image&fr=yfp-t-900&va=fuel+stabilizers


The problem comes from what you are trying to accomplish, for how long and how much degradation are you willing to accept. Nobody makes any additive to keep your fuel like it is the day you put it in. It will change just a little slower. I know some that swear by it just like Marvel Mystery oil or any other product. I know people who have used it in their planes without any real issues. Time in storage is not your friend. For lawnmowers and other types of engines that don't need high octane and is not a high performance engine these are just fine. I used to own a dive compressor business (Honda gas engines) and every spring I got a ton of calls from people leaving fuel in all winter, with and without additives, because their engine was running rough. The choke jet always needed cleaning. We need the 91 oct and can't use 87 oct. for a 912ULS with a 10.8:1 compression. The fuel storage additives may keep some things from gumming up, but can not stop evaporation. Auto fuel gives off vapors at anything above -45 degrees and no matter what container us average users stick it in and it will change and evaporate. It's just as easy to drain the fuel and throw it in a car that doesn't really care and then put fresh back in the plane. It's the best and simplest plan to use. Then there is never any guess work or extra cleaning later on.

My opinion is that the best procedure for extended storage when using auto fuel is to run it to a minimum level you are comfortable with, drain the remaining fuel. Put in 5 gal of 100LL and go make a short flight to purge the carbs and system of the auto fuel and then park it. The 100LL is stable for a long time, and the small amount of leaded fuel use will be insignificant.

We shouldn't leave any fuel in carbs for long storage. This part isn't about fuel stability.
If you are going to drain it way down why not finish it off? Why leave any fuel? Regardless of fuel type or its stability it's still 4+ month old fuel along with any by products it brought with it in bowls and wings, plus moisture / water can still sit in low spots and it will cause corrosion.
"Best practices" learned by Rotax over 32 years is to just drain and start fresh.


Would it start and run after 4+ months of left over fuel, yes, but it isn't the best practice or in your best interest.

roger lee said:

We shouldn't leave any fuel in carbs for long storage. This part isn't about fuel stability.
If you are going to drain it way down why not finish it off? Why leave any fuel? Regardless of fuel type or its stability it's still 4+ month old fuel along with any by products it brought with it in bowls and wings, plus moisture / water can still sit in low spots and it will cause corrosion.
"Best practices" learned by Rotax over 32 years is to just drain and start fresh.


Would it start and run after 4+ months of left over fuel, yes, but it isn't the best practice or in your best interest.

Click to expand...

Keep in mind that this thread was started by someone interested in storage for 4 months... so in that context I think your recommendation is way overboard (assuming something is done to flush any auto fuel out of the carbs and fuel system.

Of course everyone is entitled to there opinion... Though it seems like you often don't read everything I write.

I did say fully drain. The problem is you can't get 100% of the fuel out of the system using a simple draining procedure. That is why my recommendation is to add some stable fuel to completely flush the system.


100LL is certified to be good for at least a year. It is generally pretty low in by products or any of the other things you seem to think might be there (if it wasn't it would be meeting the requirements to have been delivered as aviation 100LL). If an airplane engine wouldn't run properly on 3 month old 100LL we would have lots more fuel related engine problems.

The impurities aren't in the delivered fuel, but the delivery system, fuel storage tanks, storage containers, wing tanks and our beloved moisture.

Like I said it will run after 4 months.

Quote:
"I did say fully drain."
"drain the remaining fuel. Put in 5 gal of 100LL and go make a short flight to purge the carbs and system of the auto fuel and then park it.



Then you said put more fuel in so I did read it as you wrote it. Fuel is fuel and fresh is better than old any day.

We have a personal choice as maintainers of our aircraft. We can perform at 100% or 80% or 60% or even down to zero.

Quote:
"I think your recommendation is way overboard'

Which percentage is overboard and what percentage is it the other way?


However I do agree at times there is more than one way to skin the proverbial cat and those are absolutely okay.
Then it becomes a personal choice. Some people tend to like Ford"s and some Chevy's, but most don't tend to like both even though they both get you there.

Either way will work here, but one is a better and practice.

4 Months? 100LL only in the tanks - no mogas. Drain carbs if you want. Block intakes for critters and bugs. Disconnect battery, maybe take home and trickle charge occasionally. Use a cover of some kind, particularly if your hangar is prone to roof leaks (like one of mine).

Oh yeah, and check the interior well to mae sure there is nothing perishable / freezable in there (had a water bottle freeze and explode, left a couple puddles).

More importantly, do a really good inspection when returning to flying service.

TODR

Hi Doug, how have you been? Time to buy another plane.


Drain the carb bowls. No matter what fuel is in them it will evaporate. It leaves a film over the tiny hole in the idle jet and at times it needs to be removed and cleaned. To give you an idea how small that hole is I take a 16 gauge wire, strip it and pull out one strand to poke and rod down through that hole. It can clog easily with old dried fuel. The 100LL in the wings isn't an issue especially if it is already there. I just don't see why anyone would drain the wings and then add fuel back in. There isn't a logical reason to do this.

roger lee said:

I just don't see why anyone would drain the wings and then add fuel back in. There isn't a logical reason to do this.

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I can't disagree with that since an RV-12 doesn't have fuel in the wings

Seriously, as already mentioned (and as you may discover once you have some specific experience with the RV-12), is that it is not easy to get every bit of fuel out of the fuel system.
Leaving any amount of auto fuel in there for 4 months is not good.
Putting in a small amount of a stable fuel like 100LL, and running the engine for a while (short flight, what ever) will purge the system.

Then, the carb bowls can be emptied if someone feels like doing so.

wings = generalized term and slip of the tongue.
fuel tank if you prefer , including header tanks