BME 50 Setup Question
 

I just maidened my DP Extra with a BME 50 inverted, BME muffler (loud), on 87 octane with Lawn Boy ashless at 40:1. I have 2 questions.

1) The engine sets up pefectly on the groung but the low /mid goes very rich in the air. Someone mentioned that I have to put a fitting on the diaphragm fitting on the carb as the ram air effect is changing the setting. The cowl is open in front and the prop blast is right on the hole.

2) I am getting a black, oily residue out of the exhaust. It is thick, nasty stuff. Definitely not metal to meatal type stuff. Am I using the right oil/mixture for breakin? Is this just a byproduct of the rich condition? Is it harmful to my engine? Engine has tons of power with a Menz 20x10s and runs well. Just starts to burble rich in the air at lower throttle settings. Any help will be appreciated. TIA, cbk

BME 50 Setup Question
 

You might try turning that plate around till it faces the back. If that doesn,t work solder a piece of brass tubing over the hole. Put a piece of fuel tubing on it and run it back near the firewall where there is dead air. As you figured its a pressure difference problem.

Black residue out the exhaust
 

I just fired up my brison 2.4 for the first time and also got the same black residue. It was black and very thick and gummy. I personally dont think it is anything to worry about. I thought about emailing Brison Aircraft to be sure. I also have the Brison 4.2 but I dont remember any black residue, but that was 5 years ago.

BLACK RESIDUE
 

Every gas engine I've broken in has spit this black residue. I'm pretty sure its just the cast iron ring breaking in. It will go away in time. Only thing I could find to get it off the covering is Simple Green.

SLC

Thanks!
 

Thanks for the input guys!! I just got off the phone with Keith from BME and he confirmed everything you guys said. Flypaper, he too recommended soldering a tube to the carb and getting it to ambient air. And the black goo is just breakin goo.
I must say that I will stick with his engines even if I did not believe they were the best (although I do). He not only called me back on his dime but was extremely pleasant, informative and patient. Thanks again Keith and RCU. cbk