Again, what is a "checkout" on a 150?
Good question glad you asked,...
might also help to know what model of 150? Also what model 172 you have been flying?
not knowing anything other than you have been flying a 172 things that come to mind at the moment...
Why and how to use the carb heat knob, sure many 172s have them, but some don't, and it is likely more critical in the 150 to use it. Just heard about a Practical test in a 150 discontinued "until you figure out the problem with your engine" due to this. Yes it was just carb ice. I think the DPE was being nice for not failing him.
How to operate the flaps, Manual flaps, different electrical switches, Flap failure modes, failure to retract scenarios.
Go around scenarios especially with flaps extended.
Performance, How close can you figure and match the book performance numbers. it can be more critical than a 172, since you are almost always near fully loaded.
Fuel Management, minimum fuel levels.
Alternator vs Generator, 12v vs 24 volt systems.
Weight and Balance
New airplane to you, required paper work. You would be surprised how many new owners don't have the AROW documents in their airplane when I do checkouts, to the point I now ask when I schedule the appointment.
that just my quick list, what else?
of course if you do your homework this checkout can go pretty quick.
Brian
CFIIG/ASEL