Running in with these ABC and ABL engines is a lot quicker than most people think.
A GMS 2000 47 is considered run in within 30 min of first running it.
A OS 46 Max AX is run in after the first tank and youhave followed the rich / lean procedure they describe in the manual. thereafter you can fly th motor in.
the fuel consumption wonltchange much from  aftet thatfirst tank till the day it dies if you have the low speed settings correct.
I have seen many people blame deadstick landings on everything from fuel to plugs to atmospheric conditions. true sometimes those are copntributing factors but 9 out of10 times its the low speed settings that too rich. Too rich and the excess fuel takes heat out  of the combustion chamber and the plug just dies.

Check you settings.

Startmotor and progressivley open the throttle to full. now dow the pinch test. The motor should immediately pick up speed before wanting to drop revs and cut out.

Now drop the revs to idle. Pinch the carb feed again the motor should run normally for  around 3-5secs before starting to choke off. release and it should recover revs.
If it is still on high idle after 6secs then you are running it too rich on the low speed needle.

Running the engine rish can also lead to plug and combustion chamber fouling. This leads to higher fuel consumption.

start off with your engine settings.</p>