Top end speed

[smeetre]

Have an 18-ft Carevelle with a 3.0 Quicksilver motor had a 14-19 pitch Quicksilver prop on it great overall prop put a hustler 21 pitch prop on it top end speed was the same but bid range was great 3000 RPMs cruise between 20 and 23 miles an hour. Top end for both props was 37 mph is there any prop out there I could get a little bit more speed?

 

[72fj40]

WOT rpm's are more important than speed. You don't want to over rev or lug your engine at wot. So, what were the rpms you were running with each of the props at wide open throttle?

 

[smeetre]

WOT rpm's are more important than speed. You don't want to over rev or lug your engine at wot. So, what were the rpms you were running with each of the props at wide open throttle?

19 pitch was at 5000and the 21 pitch brought it down to 4600

 

[jimmbo]

5000 is a little high for the 3 liter, what is the WOT rpm range for that engine. 4200 - 4600 or 4400 - 4800? The 21 might very well be the best choice.
Want more speed? Get rid of all unneeded Ballast/Weight in the boat. Wives, Kids, Mother-in-Law, can all be left ashore, especially the last one. Girlfriends and Mistresses, can remain aboard.
Proper Balancing of remaining load, fore and aft, along with proper trimming of the engine, will help.
A different lineage of prop might help, but not by much, 1/2mph perhaps.
You are held back by a Small engine in a boat that could use a lot more.

 

[Scott06]

Have an 18-ft Carevelle with a 3.0 Quicksilver motor had a 14-19 pitch Quicksilver prop on it great overall prop put a hustler 21 pitch prop on it top end speed was the same but bid range was great 3000 RPMs cruise between 20 and 23 miles an hour. Top end for both props was 37 mph is there any prop out there I could get a little bit more speed?

Not likely you need more power to go faster as jimbo laid out I had a similar size boat with 3.0 for many years. Was reliable fuel efficient and easy to work one , but speed was not its game. I used 4 blade Michigan vortex props for low end grunt spend many an hour towing kids at 4k rpm

Best thing is enjoy for what it is, get something with more power down the road

 

[airshot]

37 mph and you want more speed ??? Around here we can rarely cruise above 24-25 mph as the Lake is to rough for any more than that...running at wot for long periods of time will definetly shorten the life of your engine.

 

[Scott06]

..running at wot for long periods of time will definetly shorten the life of your engine.

Define long periods of time … I have run both of my boats (especially the 3.0) between 4-5k towing tubes skiers etc for extended periods
Of time

3.0 Lasted 25 years still had great compression (145) when I sold it ran great. On my seventh season on a 5.0 and hit it the same way full boat towing tubes boards etc.

These engines are designed if maintained to live a long life under heavy loads. Yes a stock merc can’t handle a poker run but I have beat the snot out of both my boats over a 32 year period and they have held up just fine

 

[jimmbo]

A lot of the modified Mercs can't handle a poker run either, but the same goes for any make