My 05 496 ho has only 9.6 hours. Is it OK to have the 20 hour service done at 15 or 16 hours? I'm trying to beat the spring rush when everyone brings their boat in for service. Any suggestions would be appreciated.

Not a problem.

Is there a break in?5000 rpms for 10hrs is the same 3000 rpms at 20 hrs. right?

I'm with ya Waterman. I have 12 hours on my 525 and itching to get it done! Keep to the plan brother or we'll break early!

They are broke in when you brought it home. I picked up my new 03 a couple of years ago and it had .3 hrs on it. Went straight to Sarasota Poker Run. Ran the boat on the wood all day. Had 3.9 hrs after the run on Sat. Never had a minutes problem with the boat. Sold it last year with near a hundred hrs on it. The motors are dynoed and broke in. The only thing is the drives are new. I break in my boats just like my cars. WFO

yep break it in like you are going to run it , factory motors are pretty much ready to go.

I choose to break it in. As much as your explanation is believable, I err on the side of caution.

Now that I am over 10 hours, I'm opening it up a bit, but varying the RPM. I guess that is how I would drive it after break-in anyway, so no big deal.

I was also told to keep the Merc oil until break-in then switch to Mobil 1 Synthetic. Another arguement, but that is what I plan to do.

do it to change out the old oil

But of course.