We are concidering upgrading to a boat with 850's or 1075's. What is an average amount of hours on each before a rebuilt. We do run full out sometimes but spend most of the time in the 70-75mph range which I assume would be 0 boost on these engines? Also How much are the rebuilds?

From what I have heard and read here on OSO, those motors are EXPENSIVE to rebuild.

$25k or so per 1075 if nothing's broken. 100+ hours or so before it's needed according to Mercury.

http://www.mercuryracing.com/_media/...1075_Maint.pdf

I read somewhere that the 1075 should be torn down, inspected, new seals, bearings, etc, every 25 hours. I think the cost was something like 23k.

If your loaded then the cost to purchase and rebuild these High HP engines makes no difference to you. But on the other hand if your the average boater with an average income you want reliability and low maintenance cost, stick to the lower HP motors and enjoy the boating season. I think the cost are getting rediciolus.

dont think so

I think it may have been a racing team or something that was doing it every 25 hours.

Most of the failures that I have heard of were at about 125hrs, with lifter failure. Also a couple of timing belts.
I think if you do the topend by 100 hrs, 200 before a total rebuild it reasonable.
Yes the Merc rebuilds are $$, approx $23K each for the total rebuild. But if you are the original buyer you get 25% off.

Not exactly.
They recommend that the valve lash should be checked and adjusted if needed every 25 hours.

Do they have the larger Dia lifters ?