seniorspud

My Feedback: (69)

HI I HAVE A THUNDER TIGER 61 2 STROKE HAS MAYBE 1 FULL TANK THRU IT . FOR SOME REASON IT THROWING A CHOCOLATE COLOR OILY DISCHARGE THRU THE MUFFLER USING 15 % MORGAN FUEL CAN SOME ONE GIVE AN IDEA WHATS GOING ON WITH THIS ENGINE DOES NOT SEEM TO HAVE THE POWER IT SHOULD HAVE HELP THANK YOU ALL .

countilaw

Until the ring seats, there will be a dirty discharge. What you are seeing is finely ground metal being worn from the ring and sleeve. Although there will always be dirty oil being expelled from the exhaust, it will lighten up.

The engine won't have full power until the ring seats. How long will this take, it depends on your mixture setting and the lenght of time on the engine. But figure a couple of gallons of fuel.

Frank

dasintex

My Feedback: (10)

Don't take this the wrong way because I'm not sure how much experience you have; off hand it sounds like the engine is running too Rich; read the manual and lean out the engine a bit; or like the previous post, the engine is breaking in!

earlwb

The darker oily discharge from the muffler isn't anything to worry about. It could be several factors, the fuel type you are using, a new engine being broken in, etc.  The engine is still being broken in and won't develop full power right away, it usually takes much longer than one tank of fuel. But things one can look for is to check to see if the cylinder sleeve is in crooked or not. You can look in through the exhaust and look at the cylinder sleeve to see if the exhaust ports are centered in the exhaust outlet on the crankcase. Every once in a while the cylinder sleeve can get twisted a little off so that the ports aren't aligned well.  You normally run the engine on the rich side for a while to let it get broken in good, gradually leaning it out more over time.

1QwkSport2.5r

I thought the .46 and .61 TT Pro engines are ABN? Dark colored oil is pretty normal, perhaps the engine is a little lean on 15% fuel. I get a dark colored oil from my .46, but I use 5% nitro fuel in it. Less nitro means a hotter engine temp and darker oil.

There should always be oil coming from the exhaust. Also, it takes some time for the engine to break-in before it will "run like it should". What kind of rpm on what prop are you getting and what kind of rpm are you expecting?

Sport_Pilot

Yes it is ABN and the wear from the aluminum piston will turn the oil dark till it is broken in. Nothing to worry about.

the pope

Yes abn and aim for a honey like colour . Cheers the pope

earlwb

This was after seven or eight flights that day. yes the oily residue can be a darker color. it does not mean you have a problem. It is mostly the fuel and what they put in it and the engine temperature in some cases too.

jeffie8696

Yea, that looks pretty normal. Make sure the muffler is tight, the mixture is set correctly and fly it.

Ernie Misner

Hey, that engine has 2 plugs huh? About what year were these babies made? Just using 1 plug for starting, right?

earlwb

Yes that is a 1967 vintage Fox Bluehead .60 RC glow engine. I have it in a plane today and still fly it from time to time. Besides two glow plugs, it has the great Fox 3 needle carburetor on it, with low, mid and high speed adjustments as well as an idle speed screw too.  The engine also has a steel connecting rod and needle bearings on the rod too. Yes you only need to use the glow ignitor on one plug to start it, the other plug heats up naturally when the engine is running. This engine has been on several planes so far and still works. The first plane the engine was on was a Astro Hog. In those early days no one used mufflers, so I had to remove the coupled exhaust baffle and put on a Davis Diesel Soundmaster muffler. The engine is turning a 12x6 prop at present. The engine oozes oil out of the front as the front bearing is open of course, so it is quite messy as compared to new engines of today.

Anyway the oil can be quite dark looking after it has been through the engine and exposed to sunlight, etc.

Ernie Misner

Good report Earl, thanks. Needle bearings huh. Do you still run high oil content std. fuel? Is it schnurle ported? Maybe you should box it up and save as an antique? What fun would that be though. Good job of keeping it going so well.

earlwb

Regular glow fuel, 5% nitromethane, nothing special. If I remember it has like 17% oil content, a blend of synthetic and castor oil.
It is a old style non-schnuerle ported engine, from the old days. I might as well use it rather than making it a shelf queen. Plenty of time to shelve it after I wear it out. If that is even possible,

iskandar taib

My Feedback: (5)

Black oily streaks/residue CAN mean a screw (usually a muffler screw but sometimes a mounting bolt) is loose. But it'd be BLACK, not brown, and you'll see it in the vicinity and "downwind" of whatever is loose.

Iskandar

AERORICH73

Hi Sport: I just logged onto the website to see if some info was available about RCM Plans Service, and found you engine exhaust situation. believe I sent you a personal message, but if not, Moorman the columnist for the late RC Report magazine, found that most 2 cycle engines need at least a gallon of all castor fuel run through them before they were broken in properly. At that point the exhaust oil comes out a nice yellow/clear color, and the engine will reach a good peak rpm at max throttle opening with a slight 200 rpm drop of extra fuel. Let me know how the engine is operating for you now.

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