kjkavaney

My Feedback: (72)

I have been running a used Brison 80 cc twin and find that it sprays a fair amount of black oil onto the fuse and bottom of the wings...
there is not excessive blue smoke like one would find with a cracked ring...I have tweaked the carb needles over and over and it does not seem to make any difference.
could this be a reed problem or something else ??
Any input appreciated as all this oil on a yellow airplane is getting me down...I am about to pull it and replace with a BME 76 I have..
thanks
kevin

earlwb

What is your fuel to oil ratio?
With more oil in the fuel there is more residue that gets expelled from the exhaust.

w8ye

My Feedback: (16)

It might be a matter of where and how your exhaust outlet is aimed?

The planes I see that remain clean of exhaust residue, have the muffler outlet out and away from the plane.

kjkavaney

My Feedback: (72)

1:50 AMysol...pitts mufflers with tips well below the fuse...it just seems that other people with similar exhaust do NOT see this amount of black oil all over their planes...
thanks for input so far..
kevin

CK1

My Feedback: (60)

4 options , 1) too much oil in mix
2) too rich on the needles
3) the rings are still seating (most likely cause)
4) all of the the above


Cracked ring may cause it, but unlikely
Rich needles would be easily noticed
50:1 amzoil is a good mix ratio if you are mixing it correctly.
Maybe it isnt as used as you thought and it is still breaking in

kjkavaney

My Feedback: (72)

thanks for the replies...one person did say about the rings might still not seated....hmm...maybe I should just keep flying it after all and hope it breaks in better...
easier than putting another engine on there just yet..
keep the ideas coming...
kevin

CK1

My Feedback: (60)

I would switch to a non synthetic oil or a blended oil to aid in the break in process . It will take a lot longer if ever to seat the rings on the Amzoil full synthetic oil.
Penzoil air cooled or Stihl oils are my preference . The residue may get worse for a while after switching oil but the rings will seat faster .

All Day Dan

My Feedback: (5)

Kevin, did Brison ever make a twin 80?

http://www.brisonrcengines.com/brisonengineu.htm

Do you have an image of your engine installation? Dan.

kjkavaney

My Feedback: (72)

Hi guys...I will see if I can load some pictures..yes Brison made a 78 cc engine...a twin 80 if you would...long out of production so not on the link given.
nice blue anodizing on the crankcase area...I am flying it on a SIG 1/3rd scale Space Walker with extended landing gear...
Thanks for the idea to change oils from synthetic over to lawn boy or such...the engine does look in mint condition so perhaps the rings are not seated at all as suggested on this thread.
the bolt pattern is totally different for the BME 76 I have here, so I will change gas oil and give that shot before doing anything else..
thanks for the great ideas...
kevin

kjkavaney

My Feedback: (72)

[img][/img]hopefully the picture will appear in the thread now...this was shortly before completion...
thanks for the ideas...keep em coming though..
kevin

All Day Dan

My Feedback: (5)

The exhaust stacks appear to extend about one inch below the bottom of the fuselage. With the turbulence created from the propeller it is not surprising that the residue from the exhaust is getting on the fuselage. If the engine is running all right, there is probably nothing wrong. I get plenty on my planes in the same situation and the engines are just fine. I too use Brisons and never had a ring break or wear out. I did solve the messy fuse problem a different way. Dan.

kjkavaney

My Feedback: (72)

Dan...love the color...no missing that one in the air..
I'm going to try the Lawn BOy oil and perhaps this engine is not seated yet...the guy I bought it from seemed to collect Brisons, he had everyone ever made...

thanks.

Mikecam

How does a ring leaking blow-by cause more oil to come out of the exhaust in a 2 stroke 100% oil loss lubricating system.

kjkavaney

My Feedback: (72)

Hey....thanks...now I get it...2 stroke...duh...wrong solution....
thanks for teaching me something...
I must have my mix wrong or else the carb is messed up..
I pulled the engine and sent it to Bill Jensen to be tuned up..
kevin

Truckracer

My Feedback: (19)

There have been several mentions of oil mix here. For a given oil, changing from say 50:1 to 32:1 or the other way around should produce very little exhaust residue change ... if the engine is tuned properly. Conventional oils largely burn in the combustion process so residue from these should be minimal. In fact, it has been proven many times that to a point, more oil produces more power ... but I'm sure I will be sorry for bringing that up here! On the other hand, synthetics burn to differing degrees. Some burn fairly well in the combustion process .... some do not and some are in between and partially burn. If you happen to be using one of the oils that don't burn as they go through the engine, most of that oil will be expelled from the exhaust and if the stacks are short, guess where that oil will appear.

I've never worried about the little bit of oil that comes out of a gasser. It cleans off very easily and in most cases I don't even need a cleaner. A thorough cleaning every few weeks seems more than adequate. The few times when I had what seemed like excessive residue, the exhaust stacks just barely cleared the bottom of the cowl or fuselage. Extending the stacks a bit resolved the problem.

kjkavaney

My Feedback: (72)

thanks for the oil ideas. The black stuff I get is very hard to get off, even with windex, I really have to scrub every time I fly...heck if it came off like Glow fuel would be one thing, but this is really black sticky mess...so I am thinking perhaps the oil just gets hot enough to turn to pasty oil specks that really cling to mono coat !!!
I will try other types of oil and double check my mix when I get the engine back from Bill Jensen...

I will try to figure some exhaust stack extenders as well...
Kevin

All Day Dan

My Feedback: (5)

K&S brass tubing makes great extenders for the muffler pipes. They can be held on with a couple of sheet metal screws. Dan.

kjkavaney

My Feedback: (72)

Engine back from Bill Jensen....carb was re built wrong..double gaskets...wrong gaskets. front seal on engine bad, timing was wrong...
very good communication from Mr. Jensen and very fast turn around...
I am just getting it back on the airframe but confident that it will at least run better and hopefully, cleaner !!
thanks again for all the input guys.
kevin

kerwin50

Get rid of the amsoil. It leaves alot of soot and carbons up the engine. switch to somthing like sthil ultra.
The brison 80 is a 2 stroke engine. A broken ring will not leave an oil residue like a 4 stroke will.