R912 CARB

I suppose the elevation point is somewhat subjective, but if you are flying out of 6K and always cruising higher I'd probably raise the clip to #2 slot. This time of year your density altitude could be quite high. If you do move the clip keep an eye on the EGT temps. Always remmber cold dry air can make it run leaner too. I always tell people if you don't understand carbs, fuel mixtures and the effects of temp and altitude then many times things like this may be better left alone.

The position of the clip is identical to the other carburetor. I still have to check the setting of the tank level range because the idle screw is released at 1 and a half turns. My engine has 1200 hours. Can wear cause this color change of the spark plugs?

Thanks for your interest in my problem.

Did you have this issue before you worked on the carbs or after you re-installed them? The mixture screw on the bottom of the carb should be out 1.5 turns. The idle screw up on top at the throttle arm that adjust the idle rpm can be truned any amount on each carb to balance them and set your idle rpm.

Just curious. Is the rpm drop during the mag check fairly equal and normal?

A dirty air filter can cause this. An over oil K&N air filter that restricts some air flow. Does your plane have air filters inside the cowl or does your plane get cooler outside air?   

Slight flooding in the 2 & 4 carb may cause this at low rpms. 

Dry sooty plugs usually come from taxi and or low rpm run times. They go away when up and flying at flight rpms. 

Hello,

It is a second-hand machine which has 1200h which worked at 100LL. The carbs have been revised and passed to the ultrasonic tank. For the 2/4 carburetor I all changed from the needle to the nozzle through the bushel. The idle is at least 1800 but I put at 2200. For the air filter it is new because I installed an air box which takes the air outside the hood from a naca. I have just received the fork adjustment tool and I will check its installation. At worst, replace the floats that weigh less than 7 grams. In addition, I am going to tighten the idle screw slightly towards 1 1/4 turn and redo the balancing. If there is no change, I would do the return hangar with a static with 3500 to 4000 revolutions to burn the soot on the spark plugs.

Thank you again for the troubleshooting tips.

Best regards