i replaced both of my drives from bravo xz to factory reman's xr's, and the port motor 540 around 5100 r's and above will start slipping,i can hear it and watch the tach start climbing ,i pull it back down to 4500 and it hooks up again and may or may not start slipping again, i didnt think this was possible, as im using solid flo torq hubs in the hydromotive p5x's , and i've checked the coupler ,looks and feels good... any suggestions?
scott

Swap the drives from side to side and run it
and see what it does.

Sounds like you have a water disturbance in front of one of the props. I saw this on a 36 Skater with a speedo pitot. It would disturb the water flow just enough to cavitate the prop at high rpms. Look for anything on the slipping side that is in front of the prop/drive.

hmmm,, the only thing in front is the thru hull water pick-up

If that is only on the one side that's slipping, that's a good possibility.

it has 2 one on each side and both in the same position on the bottom

I would suspect water disturbance to the prop, before I would point fingers at the drive. But swapping them from side to side may help diagnose this problem.
Anything on the bullet of the drive that might indicate a problem. Any air getting a chance to get to the prop is a problem. Is the bullet and nose cone smooth on that drive? Just thinking out loud here.. hope it helps.

D*ck

How about a better picture of the water p/u. It sure looks like it is hanging down a lot!!

Also any protrusions from farther up the hull can do it.

I'd also look at something disturbing the waterflow to the prop. Seen this before - had a customer with a Yamaha that brought me the lower unit and swore it was screwed up. After talking to him about what was going on and checking the lower unit by simply putting it in gear by hand we went to his house and checked the boat. By this time he had pretty much disassembled the mid section - powerhead hanging by only a couple of bolts - and low and behold the owner decided some time before this to "rig" an aerator pick up with PVC right in front of the motor. Put everything back together - throw the PVC riggin away - and holy hell it runs great again.

talk about a bought lesson..... LOL!!