Engine will not make power after carb install, post-overhaul

Connor,

Are you sure the Sensenich prop is not “Ground Adjustable”.  That’s different than an inflight variable pitch prop, and I don’t believe Sensenich makes a fixed pitch prop for the 912 thats not ground adjustable.  

It is not a ground adjustable propeller, it’s a solid wooden white propeller, like the kind you see on a DA-20. And I’m familiar with the manuals, however I can’t just go tearing into carbs I’m not rated for. If it was my aircraft I wouldn’t give any reference to heavy or not heavy rated, however this is a customers aircraft that also unfortunately isn’t experimental, so I can’t go all Wild West on it, so I’m following the synchronization procedure that’s in the heavy manual, referencing the videos in this website. I’m also reading other forums where people have lost power, with no progress made from their findings. All I know is we rebuilt the carbs and the engine isn’t spinning past 4750 at full open throttle stops on both carburetors. I’ll most likely send them back to motive, I’m not sure what else to poke or prod at. 

Problem/Solution Fixation, is a human trait we all can get trapped in.

Have you checked out, the air fuel in and exhaust out, as I suggested?

When you open the carbs there is a needle that controls the amount of fuel from 1/4 to 3/4 approx. Around the needle are grooves and there is a circlip usually on position #3 from the top. Lowering the circlip lifts the needle and richens the mixture going the other way leans it out.

It is relatively easy to change this.

As others say look at air restrictions and fuel restrictions. However given that pulling the choke out decreased rpm it might be too rich.

I am sure on here somewhere is a tutorial on adjusting the carbs for better tuning, there are also jet adjustments for other areas..ie the Mainjet can be adjusted for more or less fuel.

If both carbs were taken apart check the starter enrichment (chokes) were installed back onto the correct carburetors.  They are mirror image and if mixed you will have very bad fuel balance.  When you remove the 4 screws you can look at the end of the brass shaft and it will be marked with an L or R.  Refer to the heavy manual and see that they are on the correct side of the engine.  In addition check your mixture screw on the bottom of each carb and make sure it is at the factory setting of 1.5 turns out from bottom.  

Just my suggestions. 

Cheers