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

Here is an older thread with the same problem. You won’t like the cause, which was revealed on page five. Bad crankshaft. Replacement engine at a discount was the most cost effective solution. There are, however, further suggestions to try posted by others on page six.

https://www.rotax-owner.com/en/912-914-technical-questions/96-no-maximum-power-912-ul?start=20

Have we reached an outcome on this one?

So, did you resolve the issue?

Jeff Blakeslee wrote:

Regarding the jet needle setting, I don’t think that’s going to be the problem. The jet needle is out of play at WOT.  The possible swapping of the enrichment chokes is interesting.  

And Connor, you are an A&P, which is the master certificate.  There is no FAA requirement that you must take the Rotax classes to work on these engines. That being said, I agree that it’s good that you do, and I applaud your adherence to the Rotax training program. 

Incorrect.  There has already been legal interpretation that A&P's have to get specialized training before working on something they haven't been trained on.  Even an IA can't work on a Rotax without some kind of Rotax specific training. 

Connor Wilkinson wrote:

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. 

Sounds like you have a prop pitch issue if it's never had high RPM.