Cooked engine on the menu?

How can you tell if you cooked your engine?
What are the signs?
What is the best way to adjust an engine rpm?
I do not have a tach, so I adjust it by ear. (ears have plugs in them) Engine has no muffler, so it is loud.

It seems like I can not adjust the needle on this old McCoy .19 to get the rpm that we had. We are doing like 7 second laps. REAL SLOOOOW. It will not even do a wing over.

Thanks
Paul

Cooking a McCOY

1. HARD TO START
2. Low RPM'S with needle truned in.
3. Red head is now BLACK.
4. Lost the seal around case and sleeve.
5. Send it to me, and I'll take a look at it...FREE

Scott(maybe can fix)Riese

Thanks for the offer Scott.
I might take you up on it. Let me see if it is something simple. I am not for sure if it is cooked. I may have a leak some place. I am not sure I know what a cooked engine looks like. This is the Black or Grey head McCoy.

Thanks
Paul

In the case of the series 21 (Blackhead) you may have a worn out ring.

What prop are you running? I had good success with an APC 9x5 on the redhead 19 (on 52 ft lines). Some run a 9x4. If your engine is also hard to start it is probably the ring. I don't know if MECOA has McCoy 19 rings, but they might have. Frank Bowman makes very good rings.

>Thanks for the offer Scott.
>I might take you up on it. Let me see if it is something
>simple. I am not for sure if it is cooked. I may have a leak
>some place. I am not sure I know what a cooked engine looks
>like. This is the Black or Grey head McCoy.
>
>Thanks
>Paul
>
>I am a retread, - I did C/L in my youth and did not know
>what I was doing then other then having fun. And not much
>has changed.

Ron B.
F4Fguy

Paul:
Simple things first.Check the fuel system for dirt.Remove the needle valve And pressurize the tank with a fuel bulb or syringe to blow out any blockage.Reinsert the needle and repressurize to force anything out of the spraybar jets.Start it up.You'll have to re-establish your setting.Fly it.
If it still won't rev,check the backplate bolts.if they're loose ,tighten them,if they're tight,check for leaks at the backplate and cylinder to case gaskets(soapy water and flip it,look for bubbles).If it leaks,make new gaskets.You can buy the material at any auto supply.
If no leaks,check the head gasket.If it leaks,make a new one from aluminum soda can stock(you'll need about 3-4 to get the right thickness).The soda can AL is fully work hardened,to soften it,anneal it by baking it for about an hour at the oven clean setting in your home oven.You can also use .020-.032AL or copper flashing material(only one thickness).Whatever material you use,just cut a circle with diameters that will fit inside the bolts and outside the part of the head that fits in the cylinder.Do not make the metal gasket like the original fiber one.
If you have no leaks,squirt some straight oil into the exaust port and check the compression by flipping it through.Repeat with a few drops of fuel.If there's a marked difference with the oil,then,and ONLY then replace the ring.If you can find one,replace the piston at the same time.These engines have Dykes type rings and if the ring is worn,it's almost certain that the groove is also."Common Knowlege" aside,rings depend on sealing on the sides as much as on the face,especially Dykes rings.NEVER remove the ring from the piston un-necessarily.You may break it,and will almost always distort it,making it useless,or at the very least requiring a complete new breakin and needless wear.If you must remove the piston,check to be sure the ring is free and not stuck in the groove.If stuck,lacquer thinner or acetone will usually loosen it.
Incidentally,you can usually improve starting on a worn engine with a shot of oil to get an initial seal.
As to your original query about telling when it's "cooked" the most common wear point on these,and most other plain bearing engines,is the front bearing.To check,turn the prop 'til it's straight up (parallel to the cylinder)and try to wobble the prop by pulling one blade while pushing the other back and forth.You'll feel any excess play.Also listen for any clicking sounds indicating rod or wrist pin wear.
An over heat usually cooks the gasket before any real damage occurs to the piston/ring/cylinder,which is why you should check everything else first.
If I think of anything else I'll yell.

I checked the engine last night. I looked int he exhaust port and the piston looks clean. I did check the screws. I found one on the back plate that I got 1/4 of a turn on and one on the head that turned ever so slightly. Not sure if that did anything but will give it a try I hope this Saturday. If the rain holds off and the wind dies down.
How should I adjust the needle after starting? I just tweek it till it sounds smooth. I am just a sport flyer. I do not care if I get a 2x4x2 (or is it 4x2x4) break.

Thanks
Paul

Hi Paul,

Just to get the obvious out of the way, did you try replacing the glo-plug?

Also, didn't you have a broken spraybar or needle valve on this engine a while ago? Is this when the trouble started?

>I checked the engine last night. I looked int he exhaust
>port and the piston looks clean. I did check the screws. I
>found one on the back plate that I got 1/4 of a turn on and
>one on the head that turned ever so slightly. Not sure if
>that did anything but will give it a try I hope this
>Saturday. If the rain holds off and the wind dies down.
>How should I adjust the needle after starting? I just tweek
>it till it sounds smooth. I am just a sport flyer. I do not
>care if I get a 2x4x2 (or is it 4x2x4) break.
>
>Thanks
>Paul
>
>I am a retread, - I did C/L in my youth and did not know
>what I was doing then other then having fun. And not much
>has changed.

Ron B.
F4Fguy

Paul:

The thing to avoid,ALWAYS,is an over lean condition.This WILL cause overheating and loss of power.Even if you're not flying competition,a good "stunt" type run will make life a lot easier on the engine and will make learning the maneuvers a lot easier.I know your boys probably want to go as fast as they can(they're boys),but it's not good for the engine to run on the "edge"at peak speed.These McCoys will run a very nice 4/2/4 or 2/2/2and it's worth the time to learn how to set them to do what you want them to do.

Basic setting is the same for any style run.Open the needle about 3-4 turns from closed.Choke about 2 flips.If the engine is cold,put a couple of drops in the exhaust.Grab the prop firmly and turn the engine with the glow plug lit.Keep turning it over 'til you feel a "bump" against your hand.Flip the prop to start*.If it starts,and then quits it's probably too lean.Open the needle 1/4 turn and try again,opening the needle a 1/4 turn at a time until it starts and runs.
*An alternative way is to turn the prop to compression and "bump" the prop clockwise by "slapping" it.(do not "flip" it in this direction)

If it starts and runs at a low speed and sounds like it's missing,turn the needle in 1/4 turn at a time 'til it speeds up.If it starts and runs at high speed,richen the needle 'til the sound changes and it's running at a missing slow speed.The point your looking for is the point where it breaks from rich to lean.You'll hear a definite change in sound at this point.Once you've established the break point adjust the needle 1 or 2 clicks at a time until its running just on the lean side of the break point.At this point,1 or 2 clicks lean will give a 2/2/2,or rich will give a 2/4/2.You won't get it right the first time,but it's worth learning.

In flight,the 2/2/2should run steadily throughout the flight,even in maneuvers.The 4/2/4 should sound rich in level flight and "break" lean in maneuvers.You can test on the ground by abruptly pointing the nose up from a level position.The 2/2/2 should not change and the 4/2/4 should speed up.If the 2/2/2 slows without a break,it's too lean.If the 4/2/4 doesn't break it's too rich.In either case make adjustments a click at a time 'til you have what you want.

Once properly adjusted you shouldn't ever have to change the setting more than one or two clicks,altitude and weather notwithstanding.A properly adjusted engine in good repair should start in one or two flips.If it doesn't,look for the cause,plug,fuel supply,gasket leaks,etc.,pretty much in that order.

Ron,

That's a good description except I doubt a Dyke's ringed engine will "bump", at least not noticeably. I usually flip them through 8-10 times quickly and then attach the glow booster.

>Ron,
>
>That's a good description except I doubt a Dyke's ringed
>engine will "bump", at least not noticeably. I usually flip
>them through 8-10 times quickly and then attach the glow
>booster.
>
>Randy Ryan
>AMA 8500
>SAM 36
>I fly 'em all and love it!

Ron B.
F4Fguy

Randy: That's where the oil trick comes in.works 'most every time.

My K&B 4011's bump just fine. They do need to be pretty wet to do so.

>My K&B 4011's bump just fine. They do need to be pretty wet
>to do so.
>
>Jim

Ron B.
F4Fguy

Mine too,but a Series 21 McCoy sure ain't no K&B 4011!

McCoy/K&B: Ain't that the truth.

Your're right Ron about the oil, I missed the point

Ron / Randy,
I have felt this "bump" before. I did not know what it was telling me.
I have cut and pasted this post, and will take these notes to the field the next time we fly.
I hope this weekend)

Thank you very much!
Paul