After the 7th 32 ounce tank i decided to take my DL-50 apart and inspect, i noticed the top of the cylinder to have a hard layer of black crap, and the rest of the insides of the motor were clean i was using lawn boy ashless with mixed 32:1 for breaking it in

thanks e.r.

Yes - that carbon layer is quite normal - the first layer builds up pretty quick.
Why are you taking it apart so early? You are more likely to do more harm than good by doing that.

Probably normal for lawnboy oil. But not good for the engine.

Are you POSITIVE that you have it tuned and leaned out on the top end? Running excessively rich will cause carbon buildup.

I'd switch oil now. The popular thing to do is to switch to a synthetic now. I don't use synthetics and I don't have carbon problems. But it's up to you. It's your engine. I'd switch to a high quality oil and lean it out to 40:1 or 50:1. Then TUNE the needles again. Lean the high speed needle to max RPM. Use a tach if you have too. When you hit peak RPMs, richen it up about 200-300RPM and go fly it.

I'd also clean that carbon off the top of the piston before you move on. You already have it apart, might as well get rid of the carbon. I've never had carbon like that, so somebody else will have to tell you how to scrape it off. DO NOT use a steel brush!! I do know that to be true.

now its time to switch to penzoil air cooled

Yep - I wasn't going to get into that in my previoous post. I tend to run in on the likes of lawn boy for a gallon or so then switch. The carbon layer builds up like the photos show but never gets worse after that.

As RCPilet stated - make sure your engine is tuned well (like all engines should be).

thaks for the quick replies, i took it apart after reading so many posts about whats good and what isnt about oils, there is soo much controversy , i wanted to see first hand how the oil i am using is holding up



im not 100% positive i have it tuned for max performance, but i will work on it for sure tomorrow



any advice on how i can remove the carbon from my cylinder head? or will it not affect my performance

You can carefully use the sharp edge of an exacto blade to scrape the carbon off the piston dome. Don't be concerned about getting 100% of the discoloration and end up gouging the piston. Just go slow. What you see is absolutely normal for Lawnboy.

The cylinder is tougher and you need the right tools for the job. Do not use sharp edged tools for this location. The cylinder has a hard metal liner. The top of the cylinder is often soft alloy. You most certainly do not want to put grooves or divots in anything. Pe Reivers suggests a piece of broken glass and it makes sense in a way. Ball hones and soft brass conical brushes also do the trick.

Any way you go about it, before you do anything else stuff some clean cloths around the piston rod where it enters the case. That both protects the rod and keeps the crap out of the case. Whe you reassemble the engine apply a coat of whatever oil you will be running to the piston and cylinder. Not dripping but wet enough to lubricate for that first start up. Otherwise you will be starting a dry engine and that's not good at all.

thanks pat i took your advice, and used a razor blade a scotch scouring pad some gas and wd40 to get as much of the carbon off, ill turn her on tomorro hopefully it will run as good as before.

hey guy's my 2 cents. i race full size outboard drag boats, i use a product made by o.m.c. called carbon guard. mixes with your gas and no more carbon, only leaves a slight brown color on top of the piston. carbon is the number one killer of outboard motors, it gets behind the ring and grows until the ring grabs a port. so naturally i run leftover gas from my boat in my airplanes which is pump 93 octane, klotz oil and carbon guard. i get comments from fellow racers during our tear downs about how clean my motor is, well thats the only thing i do different from them. my piston will look like it comes out of the box other than the light brown color on the dome and theirs will be coated black. so the proof is there in a side by side comparison. we all run the same gas and oil.
yamaha calls their version "ring free"
cant remember what mercury calls theirs.
you only add one ounce to ten gallons so a bottle will last years, but i usually double it, don't see where it would hurt. jeff

http://cgi.ebay.com/ebaymotors/Johns...mZ160129339392 thankyou, i found the one by mercury called quickleen, theya ll do basically the same thing , i think ill go with carbon gueard.. thanks again

Pat, have you heard of or used carbon guard? I'm curious, sounds interesting.

Metalica junkie,

Perhaps you would benefit from reading the test I ran a couple of years ago. This shows the impact of some of the oils with carbon formation with higher temp running and lawnboy

http://www.geistware.com/rcmodeling/...test/index.htm

Elson

All I thinik you've done is open up a can of worms for yourself. The carbon on your piston head wouldn't have made any difference in how your engine runs at all. Now you have many things that can go wrong as you try to solve this non problem you've imagined. If you put your engine back together incorrectily, mess up the ring, scratch the cylinder, get dirt or foreign matter in the crank case you'll have done much more harm than good. Many engine manufacturers recomend Lawn Boy ashless oil for a period of several gallons before switching to synthetic oils. You're not gaining anything by switching early and certainly you will find all the experts coming out to let you know what's best. I say talk to the people who made your engine first and last. If we were all so smart here on RC universe each of us would be engine manufacturers, wouldn't we.

And who works on an engine with the prop still attached and the engine mounted in the airplane?????[][&o]

Not sure but are those metal shavings on the towel in the lower part of the picture?

some great stuff there, i just read the first page so far, very interesting, ill defiitely finish reading it tonight


i guess when im done breaking in ill use bel ray, or penzoil... thats too bad , i went halfers on a case of amsoil saber

no they arent metal shaving from the engine, but from a scouring pad, i made sure none got in the engine. I reassembled and test ran my engine and it ran just as good as befor (thank God). I guess a little carbon is normal, i probably wont take my engine apart for a lonnng time.




i realized that, i just got over concerned by reading all these topics about engile oil, ratios, and carbon build up. Im just gonna continue using my engine normally use a sensible ratio of oil to gas, and adjust it properly, and try not to worry about the little things. And next time ill take off my prop ...lol

Carbon deposits on the piston crown are normal. In mineral oil they are quite hard, but with synthetic oil they are soft and do not tend to grow much.
The carbon should not extend to the piston ring lands, where it will lead to ring sticking. Once the rings stick, exhaust gas blow-by will cause pistons to seize because the heat flow from piston to cylinder is disrupted.
When racing, I found some carbon on the piston skirt useful when running a mineral (dynosoar)/castor oil blend, just enough to fill in any irregularities so the piston could ride on a full oil film. Modern "synthetics" will clean very well, and prevent these deposits.
BTW,
Lawn boy is not an oil I would consider for my air cooled high performance engines, though it will probably perform well in lowly loaded weed cutters and chain saws. Ask professional lumberjacks what they use. Their saws have to work a lot harder, but then not quite as hard as our model airplane engines. A chainsaw engine has forced blower cooling and gets cooling pauses, which save their day.

I have not used carbon guard because I've never had a need to. Running just a taste rich with a good oil at a reasonable ratio let's the detergents in the oil and gas wash away about 98% of carbon and other wear products.

Fancman,

If I wanted to work for next to nothing it would be a simple process to make and distribute my own engines. If I charged what they would be worth no one would buy them because they would be priced alongside DA, ZDZ, Brillelli, 3W, and Taurus.

Thanks for the reply on the carbon guard Pat. I have found a few very good oils that will clean the carbon up from the bad oils that I have tested so those are the ones I am sticking with. I didn't feel a need to try it, just wondering if you had any input on it.

guy's i'm not preaching that you have to run this stuff but i can with pictures in the future prove that it works. whats a few extra bucks for someting that wont let any carbon generate in the cylinder. this stuff didn't become popular untill the direct injected engines became popular in the late 90's. the injector is in the top of the cylinder head that way the exhaust port is completely closed before the fuel is given to the cylinder. bad part is the injector is in the worst spot for carbon, top of the head. so these expert bass fisherman who spend hundreds in baits wont spring a few extra bucks for the oil that is required for the engine. so after a season of wal-mart super-tec which doesnt clean like a good detergent oil, the injector clogs with carbon and smokes the powerhead becuse it runs lean. then i get to hear about their 500 dollar a month boat note, 700 hundred dollar truck note and how they cant afford to fix the motor. a month later the bank calls me and says lock up the boat! moral of the story is spend 15.00 bucks every two years for 16 ounces of insurance. whats it gonna hurt to have something in the gas that PREVENTS carbon build up. jeff

Makes sense to me.

Jeff, I am sure there are applications where it would be the cat's meow. I just don't see a need for it in my particular situation. Not saying anything's wrong or it's a bad idea, I just don't need anything like it "at this time". Things may change later, who knows!

Are you all aware DA RUNS THE ENGINE FOR ONE HOUR BEFORE YOU GET IT ????????? IT WILL NOT BE SPOTLESS WHEN YOU GET IT.