I noticed my pretty new DL50's exhaust residue is oily. The residue collected in the muffler can sometime drip off after a run. The engine is in break-in period and Low needle is 1.25 turns out and High 1.5 turns out.

This does not happen to my other gas engines though. Their residues are rather "dry".

Just wonder if oily residue is characteristic to DL50.

What break in oil are you using?
We have been using Penziol @ 32 to 1 with a small
of residue... NOT clean but also NOT dripping...

Walt...

usually for breakin i use a pertol based oil and after the break in i go to fully syntc'
residue is while on reach for breakin
i'm really want to get this engine for my self as well
share as much as possible
good luck

that is normal for breaking in

I'm having same issue with my DL. Black oil, not exactly dripping, but spotting up my nice white covering. I am using Lawnboy at 32:1 with intent to go to Bel Ray 50:1 after I use up the Lawnboy. So far only three flights, but plenty of power.

Normal condition for any new gasser. Can be improved with proper tuning. Condition will mostly go away with time and when you change to the 50:1 mix but any gasser will produce a spot of oil from time to time. These are oil burning 2 stoke engines after all. If you want 100% clean .... there's always electric.

Well, if you own a DA engine, you will know the difference. DA's exhaust is definitely less visible at the muffler exit.

I'll take the advice that it has not been broken-in yet.

one more thing
at NITRO engine when you have black oil residue it means that the engine is about to end he's life - or one of the main parts such as sleev/piston/ring etc'.
somtimes it is the the crank shaft rear part scratching the back plat.

in GAS engine this can be the issue as well, assuming that the engine is new and have no factory/manufacturing screwups i would suggest to try and replace the oil type.

you got a 400-800$ ARF with another 400$ new engine and another 300-400$ RX+servos, why not go and buy the best oil money can get??? for 1L it will cost no more than 20-30$ TOPS.
both oils the petrol; and sync' ones - go and get the best there is.
i belive that this will reduce the residues that you see.


good luck

shalom from sunny Israel and Happy Passover .

I am using Penziol. 32:1. The same mix that goes to my DA50.

The difference of exhaust is striking.

The DL has very good compression.

Probably has more to do with how the exhaust gasses leave the airflow. Sounds like the DL's exhaust/oil gets caught by propwash more than the DA50 does. I am always amazed at how much of the goop manages to find a way to stick to the plane. Doesn't have a thing to do with being broken in. Has lots to do with how the engins is tuned.
It's also why I figure out a way to mount a muffler with a exhaust stinger to help eject the goopie mess. When done installing muffs I usualy can go 3 to 5 days of flying before needing to clean.