so the motor went out on my condenser. I replaced it and the fan blades thinking the orignal seemed a bit out of balance.
both are generic parts, a dayco fan motor and blade.
so I was standing near it today mowing, and it feels like air is being pulled in from the sides, but blown out the front of the condenser. The air flow out the top does not seem to be as good as the second smaller unit.

I was afraid I had the fan wired backwards and it was sucking air from the top or something. So I reversed it and it then started sucking from the top, so I put it back.

there seems to be a shroud around the fan blades. I thought I seated it as far down as the blades would go without hitting anything, but maybe it could go further?
is that my problem? or am I just making the difference up?

I am pretty sure the sides of the smaller unit was measure 92, and the unit I fixed measured 106 at the coils with an ir temp gun.  so I am concerned about the air flow. But different size units may be the difference.

ok, I think I figured it out.
the replacment motor is thicker than the original. so it spaces the fan outside of the shroud.

do they make replacment longer shrouds?

It is pretty much always better to just order the correct factory parts so you don't have to deal with all this crap. Most motors are not reversible unless it is clearly noted or it is 3-phase.

How did you select the replacement motor?
Did you check amperage draw?
How is the pitch of the new blade compared to the old?
What about the size of the blade?

granger matched it up on amps, hp and a few other things as well as the pitch and blade size on the fan.
the motor is reversable. has a plug just for that.

it clearly is that the fan isn't deep enough into the shroud, so some of the air isn't directed up like it should be.

I will probably use roof flashing to make the shroud slightly longer and that should take care of it.