Hydrolic lock on 912 ULS

[Paul_G]

After 8 months of not flying my Sirius TL 3000, I was doing my preflight and found I was unable to rotate the prop to burp the 912 ULS. After removing the spark plugs, I found two cylinders full of oil.

Coments appreciated.

[Warmi]

Are you using Rotax branded oil filters only ?
From what I heard this can happen if the engine is sitting over long time and if you are using non Rotax filters( without a check valve )...

[Paul_G]

Rotax only. Yes.

[drseti]

Are you in the habit of burping your engine after each flight? Specifically, was the engine burped prior to sitting unflown for 8 months? If not, I would suggest an oil change with new filter before you try to start the engine.

But, coupled with the electrical issue you reported on a previous thread, I would procede very cautiously. One wonders what other defects might have crept in with the engine sitting idle for so long. The Rotax Line Maintenance Manual lists specific steps for preparing an engine for long-term storage. And 8 months certainly is long-term.

[Paul_G]

I did burp the engine after my last flight 8 months ago. I was planning on a flight from Washington to Southern California, but the weather did not cooperate. This issue actually happened in mid June and I removed all spark plugs and let the oil drain out. It only entered the front left cylinder with a small amount in the left rear cylinder. After cleaning the plugs, everything cleared up. My mechanic told me that if I had tried starting it, it would have bent the rod and needed a complete teardown. Another good reason to always burp before you start.

[ShawnM]

Another good reason to always burp before you start.

For sure, this is the only time I burp, before the first flight of the day, I don't burp after a flight, not sure why this is necessary but I'm sure someone might have an answer. It takes less than a minute to burp my 912 but I also don't let it sit for 8 months.

There was one time during my training I couldn't fly my plane and it sat about 5 weeks but I still went to the airport probably twice in that 5 weeks to start the plane and let it warm up.

[drseti]

I don't burp after a flight, not sure why this is necessary but I'm sure someone might have an answer.

Engine burps more easily when warm, so it might save you some effort the next day (or week, or month...) Also, burping before the plane sits for a prolonged time might prevent hydraulic lock (although that didn't seem to have helped Paul G...)

[drseti]

There was one time during my training I couldn't fly my plane and it sat about 5 weeks but I still went to the airport probably twice in that 5 weeks to start the plane and let it warm up.

Opinions vary as to whether this is beneficial or not. It has been suggested (in Rotax classes) that running up the engine doesn't get the oil hot enough for accumulated moisture to boil off, but actually flying the plane does.

[Paul_G]

I had to leave my plane up north for the winter because of weather...and then the virus came to town. We had to stay away longer then we planned.

I must have forgot how to spell while we were sheltered-in-place. Hydrolic = Hydraulic

Thanks for all the comments.

[drseti]

I must have forgot how to spell while we were sheltered-in-place.

That's OK, Paul. We don't teak of for speling hear.

[ShawnM]

There was one time during my training I couldn't fly my plane and it sat about 5 weeks but I still went to the airport probably twice in that 5 weeks to start the plane and let it warm up.

Opinions vary as to whether this is beneficial or not. It has been suggested (in Rotax classes) that running up the engine doesn't get the oil hot enough for accumulated moisture to boil off, but actually flying the plane does.

Thanks Paul, this I do know and have also heard it from many LSRM's. My oil doesn't really get hot enough in flight to burn off moisture either as it never reaches 212°. In my case I just wanted to run the engine to get the fuel moving around and not let it get stale in the carbs or fuel lines. I don't like it when my plane doesn't run at least once a week.

[Warmi]

There was one time during my training I couldn't fly my plane and it sat about 5 weeks but I still went to the airport probably twice in that 5 weeks to start the plane and let it warm up.

Opinions vary as to whether this is beneficial or not. It has been suggested (in Rotax classes) that running up the engine doesn't get the oil hot enough for accumulated moisture to boil off, but actually flying the plane does.

Thanks Paul, this I do know and have also heard it from many LSRM's. My oil doesn't really get hot enough in flight to burn off moisture either as it never reaches 212°. In my case I just wanted to run the engine to get the fuel moving around and not let it get stale in the carbs or fuel lines. I don't like it when my plane doesn't run at least once a week.

Here is somebody on the Rotax forum claiming that running your engine on the ground only is actually worse than not running it at all.

https://www.rotax-owner.com/en/general- ... -vent-tube

I can tell you from my experience , early this year I had my plane down for a few weeks with only ground engine runs being done every few days and my oil tank cap started dripping with condensed water and soon enough the dipstick started to corrode etc .. all of that went away I soon as I got up in the air.

[RTK]

I don't like it when my plane doesn't run at least once a week.

Ooof! I'm a bad airplane parent. I go weeks without starting my plane. It's sad. I think my family comes up with reasons to go with me to the airport to distract me and keep me from flying. (My wife is not keen to fly at all, and my son is lukewarm to the idea.)

The Rotax is a dry sump system, so I burp the plane before any flight to ensure that the oil has circulated through the engine and lubricated any surfaces prior to startup. After sitting for a couple of weeks, it may take 30-40 rotations of the prop to get the oil circulated. I've resorted to using mechanics' padded gloves to burp the engine since my hands get raw and tired gripping my 2 bladed prop and rotating around. I imagine those of you with 3 bladed props probably have it a little easier.

[drseti]

I don't like it when my plane doesn't run at least once a week.

Your plane doesn't like not being run either, Shawn. (Oh, wait - I really shouldn't anthropomorphize intimate objects. They hate that!)

[ShawnM]

I imagine those of you with 3 bladed props probably have it a little easier.

I have the 3 bladed Woodcomp and it does make the "reach" for the next blade a little easier. Remember to go slowly and even slower on the compression stroke and she'll burp quicker.

I don't like it when my plane doesn't run at least once a week.

Your plane doesn't like not being run either, Shawn. (Oh, wait - I really shouldn't anthropomorphize intimate objects. They hate that!)

No worries Paul, Ginger doesn't mind, she actually likes it.