Re: Black exhaust smoke and residue...

Jul 05, 2003 2 Replies

This symptom can be caused by normal vibration. Check that the muffler is affixed tightly to the engine, and that the muffler halves are not loose.



Cheers,



I have what I believe is a problem and I want some input on it. I've got a
> OS FS 60 2-stroke that has started putting out BLACK smoke and oil residue.
> It's a pretty nasty color black. I'm concerned because all of my other
> engines put out fuel colored (pink/red) oil residue. The engine is 6 mos old
> and has had about a gallon of fuel through it. Prior ot that, I ran about 4
> tanks full through it very rich as per the instructions t break it in. I did
> buy it used. the person I bought it from said that he had only ran 2-3 tanks
> full through it to break it in. It used to put out red oil residue. motion
> seems free and it still seems to run fine.
> Have I run it too lean and am now burning engine? Is there anything I can do
> about it? should I inspect it in some way to see what is going on? I'm not
> afraid to take it apart, btu I don't know that I would recognize a problem
> if I saw it.
> I look forward to ya'lls input.
> thanx
> Mark
>
>

That is caused by some aluminum (usually the muffler) vibrating/rubbing somewhere. The black stuff is actually the very fine aluminum grit or cast-off in the exhaust. It is NOT caused by any break down in the running gear of the engine, that is, the piston, connecting rod, or crankshaft as there is no pure aluminum there. Tighten up everything and the problem will go away.

Yes, a loose muffler can cause dark oil, but there are also other possibilities, such as fuel.

After running many gallons of CoolPower through my Super Tigre G.61 I switched to another brand of fuel and immediately started getting a dark oil collection on the tail. When I switched back to my previous brand of fuel, the symptoms went away. When I took a gander at the internals, there was very noticeable wear to the cylinder.

Try a different fuel brand and see what happens.

Dave

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