Determining max rpm and correct prop

[litespeed999]

I've been trying to determine if I have the optimal prop for my boat and one of the pieces of information I need is max. rpm or max RPM range for my engine. I have a 1993 240 OVR with a 7.4l Mercruiser and Bravo One drive. The prop is a Stainless 3 blade Quicksilver Mirage with the numbers 48-13700-19 so I assume it is a 13.7" dia. with 19" pitch.

Would this be the original prop? What is the optimal RPM range for this boat/engine at WOT? I'm just looking all around good performance on Lake Michigan and the smaller interior lakes.

Thanks is advance!

E

 

[sbw1]

The WOT spec for that 454 engine is 4200-4600 rpms. Install a prop that gets you into that range at wide open throttle and you have an acceptable prop.

 

[Lazy Daze]

FYI, there is a prop chart on Sea Ray's website that lists the original prop based on engine and drive for each model. There may have been multiple versions of the 454 used that year, so take that into account. But, the best way is to get out there and run the boat. Personally, I like propping a boat based on my "normal" load rather than the very light load that the manufacturers test with.

 

[mojocowboy]

The WOT spec for that 454 engine is 4200-4600 rpms. Install a prop that gets you into that range at wide open throttle and you have an acceptable prop.

Is there a place I can find the same info for my 4.3 efi.

 

[sbw1]

4400-4800 rpms is the spec'd WOT for each version of the merc v6 according to a manual I found online. I do not have any experience with this particular engine. You can probably find all you want to know about 4.3efis by googling 4.3efi WOT specs. There are many new and remanufactured ones for sale including manuals for various versions.