Engine RPMs

[mikehedb]

I was wondering if anyone has RPM info for the 33FBC with 330 Mercruisers. My boat is a 1977 and I now have two fresh 454 engines one is a year old and the other about two months old. I have not reworked the props yet...I believe they are either 20x20 or 20x19. The boat has a half tower with sunbrella top and a 4 sided enclosure of the flybridge. At WOT it looks like I'm getting 4000rpms. At cruise 3000-3100prm I'm running 21.5-22.5 MPH. One of the old Mercriser valve covers had a sticker which said max RPM 3800-4200RPMs. Should I expect to get more RPMs at WOT, or prop the boat to get to 4200 RPM, or is 4000max RPM good for my set up? It seems like 3000-3100 RPMs is a good cruise speed...any comments. I like to sray out of the secondaries on the carbs, or I may as well just stand over the engine and pour gas in them. I'm getting ready to have the props refinished so I'm looking for a little guidance before doing so.

[dougl33]

I think 4k is OK, but you may be better off propping them to 4200rpms. When I had gas, I would cruise at 3100-3200rpm. That was good for 18-19 knots.

[Rick]

Yeah, you can get a little more out of them. Rick Ticket 85 SF Merc 454 MPI's Falmouth, MA