"Don Dando" wrote in message
t...
It has been my experience that higher Rpm's within reason are a lot better
for an engine that lugging it down. We rebuild a lot of motors that have
had too big of a prop with ceased rings. Engines run at higher Rpm's stay
cleaner. You can run your engine at 7,000 - 8,000 Rpm's safely.

The 500 Rpm difference you mention is if no significance.

Don Dando


Don, when you reply to posts use the "Reply Group" button instead of the new
post button. The "New Post" button starts a new discussion thread so your
comments sometimes might get missed in the discussion.

As far as the 7-8,000 rpm if the motor is rated 90 hp at 5500 rpm and the
other Merc motors of that similar size are rated at 5000 rpm I would not be
willing to take the financial risk of overrevving a motor that much. (This
is my first big OB motor).

I think it's similar to the fact that a SB Chevy V-8 can be built to safely
rev to 9,000 rpms or more but you wouldn' want to take a stock Chevy SB and
do that, it would probably self destruct at around 7500 - 8000 rpm if the
computer would allow it to go that high. most stop at around 5500-6250 max.


Fredo