Yanmar 315 not reaching max rpm

[Big Dipper]

I have yanmar 315 with bravo 3 on a 9m cabin rib, from new wot only got to 3550 revs, seemed to get more sluggish getting up on the plane as I added weight, though still maxed out at 3550 so at 150 hrs changed from 22'' to 20'' props, expecting to get close to 3800 recommeded wot rpm. Gets up slightly faster but tops out at 3600 (or slightly above), any ideas?

[donegaldan]

Hey Big dipper,
I have ran those yanmar 315's a lot hotter than that, in similar size boats.
You are right tho, something sounds pretty wrong, the new prop's obviously are the first thing to try, but sounds like either a monday morning engine, or badly set up.
just a bit confused, did you re-engine the 7.4 Redbay ?
Even a 9m Redbay cabin will run hotter than that.

If you want to PM me with some more info on the problem, happy to see if i come up with any suggestions. I may have some guys i can ask some advice on it for you if you want. What kinda speed are you getting when you are WOT ?

Happy ribbing...
D