Sleeve has a yellow spot on it?
 

Pulled my sleeve out of my OS 65 LA to take a look at it after running it a little warm last time I flew it. It was lean the first flight of the day, landed and gave it a couple more clicks. It flew fine 3 or 4 more flights, but the cylinder has a yellow goldish spot, and the top of the cylinder is blue. What am I looking at here??

RE: Sleeve has a yellow spot on it?
 

Looks like the nickel is coming off the sleeve








l

RE: Sleeve has a yellow spot on it?
 

Interesting looking sleeve.

Looks like baked on lube inside. It'll be from black to the gold, and the gold can be very pale and translucent. Look into your muffler and the inside of the exhaust stack. Same stuff only darker.

The areas on the top flange could be where the chrome plating didn't cover. It isn't critical up there and might have been machined off if the sleeve was deburred or finish milled after plating.

When plating fails in the combustion chamber you'd expect to see scoring and the piston would show matching scoring. OS says the sleeve is chrome plated and the piston is aluminum. You'd think the piston would have attracted your attention for sure.

RE: Sleeve has a yellow spot on it?
 

Yep...looks like "O.S. disease"...:eek:

RE: Sleeve has a yellow spot on it?
 

Its nice and smooth, no deep scratches. I did run it too lean with 10% Cruel Power. I was in the air 4-5 minutes and it started slowing down to maybe 5k rpm at wot. I pulled back the stick and landed it still idling. I let it cool down for a few min, fueled it back up and started it. At wot, it was 1-2 clicks past peak rpm. I retuned it at about 300-400 under max rpm and flew it for a couple of 15min tanks. It seemed to fly fine. Do I just keep flying it?? I dont think $68 to re-sleeve it is worth it. I'll just fly it as is and try and baby it..

RE: Sleeve has a yellow spot on it?
 

"It seemed to fly fine."

And it is fine if that's true. And experience says that no doubt it is true.

You call it "Cruel Power", but you owe it an apology. It is the reason for the "nice and smooth" liner and piston. And of course your quick response to the slow down.

RE: Sleeve has a yellow spot on it?
 

Really?? I have around 60 flights on this engine, and after this happened, it rolled out the same, climbed the same and had no noticeable difference in speed. I'm here asking for input on the sleeve, not weather I'm telling the truth or not. And the Cruel Power was a dig on my self for putting a mistuned engine in the air with full synthetic fuel in it.

RE: Sleeve has a yellow spot on it?
 

Good grief fly it. trying to rationalize a problem by color on a sleeve is almost impossible but then you said there is no problem. Scoring or flakling is a different matter.

Of course a smidge of castor in your fuel mix as a precaution aginst one of these lean run incidents should always be standard operating procedure.


John

RE: Sleeve has a yellow spot on it?
 

I agree just fly it, and Castor is just cheap insurence. You can buy just as good of a fuel with castor in it as your cruel Power ( which isnt a bad fuel at all ) As the OP posted though he tuned it not the fuel, but CP isnt very forgiving

RE: Sleeve has a yellow spot on it?
 

When power master became hard to find, I started to use coolpower. Now that I have PM stocked back up, I was just running out the last of my CP. Still my fault, but the thread was started because of the yellow spot on the cylinder not because of the fuel. No flaking or deep scratches, so I will run it as is and not worry about........ Now if I can just stop worrying about spektrum brownouts! (joking) :-)