TimR

I bought a jug of Sig Champion 15% (50/50 Syn/Castrol mix) Rc fuel because the store ran out of Cool Power (pure Syn) that I normally use. It ran OK a first, but then the low end side of the carb became fussy. Minor tweak and it worked fine. Nice low idle, not as fast high end as when I ran cool power.

My question is the exhaust residue came out black. But not mettalic as if the engine was wearing at a horrible rate. Is this normal?
Did I fry the engine?

The cool power exhaust was clean with a green tint to it. So I would think that the Sig fuel would be clear but have a pink tint. The fuel is recent.

Did I fry the engine.

Help.......

Thanks
Tim

Gollywock

Hi Tim- You didn't harm your engine at all. What you are seeing is residue from the castor oil. Castor oil is actually a better lubricant than synthetic but somewhat messier. Jim

Super Splatter

It's soot from the castor, Sig has lots of castor

TimR

Thanks guys for your response. I didn't think of soot, but that's what I would identify it as. I didn't know castor oil did that. I've been using Cool power since I've started RC.

Is it it more sooty the hotter you run your engines?

Thanks
Tim

TLH101

My Feedback: (90)

Your motors will live longer using the castor blend fuel. It helps prevent rust & corrosion. Also make them more tolerant to an occasional lean run, or overheat.
It will also make your engines look worse, due to brown crud build-up.
I always use a castor blend fuel in all my glow engines.

jaka

Hi!
Well if you run castor based fuel ( or any other fuel for that matter)you should never see totally black oil comming from the exhaust...then you know that your engine is running too lean. simple as that!!!
So open up your high speed needle somewhat

Regards!
Jan K

Ross Kean

The black may be simply due to a loose muffler bolt. In many two strokes (especially if you are not using a muffler gasket) the oil will come out black due to minute particles of aluminum caused by the mating surfaces vibrating against each other. Try tightening them up and see if the problem goes away.

Ross

TimR

Jaka,

I did richened the high side a little, but not much. Very soupy exhaust and I had a smoke stream when it flew. The engine has a very nice high end. I set the high end with the engine crank pointed at the sky. I lean the high speed out until it starts to lose rpm's, and then I richened up a little past max rpm. It wasn't totally black but you can notice the sooty film splattered on the tail feathers. I have an hobbico exhaust diverter on the muffler which is short. What would be the lose if I ran a tube down to the landing gear? Would the effects be like a tuned pipe? RPM lose?

Ross
There are only two nuts & bolts for the muffler and they hold the muffler onto the engine. And where the muffler and the exhaust port mate, it is very clean. I even disassemble the engine and muffler to check for any damage.

Once I got the high side set and the low side set, it ran great. This Supre Tiger .51 is a great engine

broke_n_bummin

When all is said and done, you probably did your engine a favor. The black soot is normal. especially if you've been running nothing but synth. Castor doesn't break down as easilly as synth.