How much hp can a xr drive handle with 1.5 gears

Merc says 600,

The real question is how much hp for how long???

There are plenty of threads with real experiences in this section that you can go back and read.

Rough water/re-entries; That's what kills them.

I am running 750 thru an Bravo XZ rebuilt by Mr. Gadgets on a 25 Checkmate with about 70 hours so far. I am easy on the hole shots and try to keep it in the water. If you drive it like you stole I am sure it wouldn't last long. I believe people are having better luck with the XZ drive lately because the new XR gears are not as durable as the old ones. On one of the recent episodes of Boost Power TV Alexi talks about the XZ drive versus the XR drive.

Well my b1s with all upgrades, shafts and gears held up well.New xrs second time out and it was a rough day. locked one in gear and broke shift fork in the other, The first time the universal came apart and destroyed the upper case. sure makes me wonder.
Rich

My last boat with a 525efi seemed to make short work of an XR. I was running a Maximus prop which are tough on drives.

I blew a Bravo X1 upper in 7 hours of running on the Great Lakes after putting in my 525. I replaced it with an old style XR upper which lasted two seasons before the input shaft bearing pre-load nut backed off and eventually the upper broke catastrophically. I didn't know they needed to be hard shimmed or at least loc-tited. My replacement old style, hard shimmed, XR upper has been going strong. After last season I had to replace the gears in my Imco shorty (bravo gears) due to normal wear after about 6 seasons. 4 blade prop and lots of air and re-entries. I try but no one can be perfect on the throttle.

What gear oil should i run for over horsepowered xr drive trying to prolong it. been running just merc quicksilver but went up in hp this year