3.0 l Merc. RPM's limited to 4k at WOT Why?

[mikegrant]

I have a 3.0 L Merc. The engine was rebuilt/placed by my service folks due to a winterizing error. The new engine runs great however I can't seem to get the RPM's up above 4k. According to my literature the maximum recommended RPM for my engine should be between 4400 and 4800.<br /><br />I have put in the recommended 20 hours of engine breakin....varying speeds/loads etc....no high rpm running until the later hours of breakin.<br /><br />Any thoughts why I am having this problem?

 

[tommays]

Re: 3.0 l Merc. RPM's limited to 4k at WOT Why?

how fast is the boat now compared with the old motor its possable your tack is reading low i have a 3.0 on a maxium 2000 sc and even going from a 14*19 prop to a 15*17 makes a huge difference in wot and boat speed<br /><br />tommays

 

[mikegrant]

Re: 3.0 l Merc. RPM's limited to 4k at WOT Why?

It used to top out at 39mph at least per the speedo on the dash...<br /><br />now I get maybe 36mpg.<br /><br />I'm not dying for speed, but I was curious why the change occurred.<br /><br />thanks