Strange wetness in cylinders

[NorthIdahoAvidflyer 374]

I took the Avid out of the garage and ran it for a little bit. This is the second time I’ve ran it since installing the new rotary oil hoses and replacing the exhaust. The first run showed no issues and ran fine. It was not running as smooth as normal on the second run. I ran it for about 5 mins then shut it down. I had to run to town so I pushed it back into the garage. When I was putting it away I noticed moisture had came out the first exhaust bend and had sprayed black liquid all over the firewall and down the side of the plane. It wipped up easily. I pulled the plugs the next day to see if they were wet. Sure enough they were all very wet. The back cylinder had enough to catch in a clear laundry soap cup. It was a fine oily liquid. I tasted some and it was not sweet like antifreeze. It was not purple which is the color of the Quicksilver full Synthetic pre-mix I use and it was not green like the Semi Synthetic Quicksilver oil I run in the Rotory Valve system. It’s oily to taste and a brownish color. 

I checked the float bowls and they look normal with no sign of water. The only thing I have not done is drain the header tank.

It could be some of the old oil that was left in the rotory valve system. I did have the plane on it’s nose to bleed the rotory system of air. 

Any ideas? This one has me baffled. 

 

 

[NorthIdahoAvidflyer 374]

I drained the header tank. No issues there. I found the oil I drained out of the Rotory Valve system. It’s green and much heavier. I primed the engine a lot to get it to run after setting for a few weeks I’m wondering if I flooded it and didn’t run it enough to clear it up. I pulled the plugs and will dry everything out and run it again this week. 

[ChrisBolkan 130]

Sometimes on my 582, not very often, I would run into a similar problem. i figured it was the position the oil pump was in in its rotation the last time I shut down allowed oil to leak into the cylinder. Sometimes also not very often the plugs would be wetted in gasoline (with some oil). These things happened so infrequently I never really figured out the reason or ever had to do anything specific about it. One thing is for sure with the engine mounted up side down, the cylinders will fill with anything that leaks and once in a while things do leak.

This might not make you feel better or provide a solution, stuff like this does happen occasionally with inverted engines. After taking my 582's apart a few times and having one main bearing ball retainer fail (thank god the bearing did not fail) I grew to wish Avid had not chosen to mount the engine inverted. One of the nice things Rotax did with the 582 was provide a little funnel that collects condensed oil on the block and channels it to the main bearings. This feature does not work with the engine inverted.

[NorthIdahoAvidflyer 374]

Yeah there was no real evidence that it was one thing. I come to the same conclusion as you. I think it was a mixture of oil left in the crankcase along with some fuel. none of the other fluids share color or consistency with what i found. I also had not turned off the gas like I normally do between runs. 

I pulled the plugs last night and cleaned them. I will reinstall them and run it again this week.

Thanks Chris 

[ChrisBolkan 130]

You might need new plugs. When mine have been wetted in the past I could not seem to get them to work right again even after cleaning.

[NorthIdahoAvidflyer 374]

I will try a new set of plugs. I ran it and it ran ok but it still does not seem to run as smooth as before. It is still cold here and the temps and barometric pressure is lower than when I ran it last summer. I am going to lower the needle, turn out the idle mixture screw out and see if that helps. 

What plugs do you run Chris?

Thanks for the input.

 

[Dusty 126]

What EGT's are you getting?and at what part of the rev range? Lowering the needle has limited effect at idle 

[ChrisBolkan 130]

NGK BR8ES SOLID TOP plugs.

You have to specifically search for solid top plugs, that is ones that the cap does not unscrew off of. The "secrew off"  BR8ES plugs look identical but should NEVER be used because the screw off top is made of aluminium and it will either unscrew and the plug wire fall off or the plug cap will wear thru the aluminium top and it will fall off. 

Don't ask me how I know :-) 

[1avidflyer 1983]

I do have to say that I've used the screw on cap plugs often.  Rather have the others, but in in a pinch....  I would take the cap off,  squeeze it with pliers to slightly flatten it, so then it fit tighter when screwed back on, and was less likely to come off.  Another thing I always did on the inverted engines was make a loop of safety wire on the bottom of the plug, and use a zip tie around the spark plug wire so it could never come off.  JImChuk

[NorthIdahoAvidflyer 374]

What EGT's are you getting?and at what part of the rev range? Lowering the needle has limited effect at idle 

Yes my EGT's are running lower than normal hence the reason for the needle adjustment. The aircrew adjustment is for the idle current. I will most likely change the idle jet.

[Dusty 126]

The standard idle jet is way too rich.The 912 jet (35) is way better, but if you are premixing the #45 would be safer.

egt above 950 at idle is good!

[akflyer 1427]

on the inverted engines the oil residue and gas will run down the cylinder walls and collect in the plugs.  If left to sit for extended periods of time they will fill up with oil etc.  Normally a good shot of primer will still get them to fire off but depending on what oil your running they may foul quicker.  As with anything with an engine, prolonged storage is the worst thing you can do for them.  A quick start up and shut down is really hard on them.  If your going to fire it off make sure you can get it up to full temo to cook the moisture out of the cylinders.

 

[skypics 89]

When I was driving a 582 I learned early, especially on an Avid with the engine upside down, to only use the primer when the starter is engaged. Otherwise, the engine could quickly flood and the plugs had to be removed and cleaned.

 

John M