prop help?

[sburner]

I have a 20' Seaway cuddy cabin with a 150 h.p. Johnson Ocean Runner. At wot i was only getting 4800 rpm's. At 4000 rpm's i was going about 24 mph. Not sure what the pitch of the prop was but I had it turned down to a 13 pitch. Now I'm getting 5200 rpm's at wot. At 4000 rpm's I only get about 19 mph. Does this sound right? The engine now sounds and feels right and I get on plane quicker. Can I now run the boat at 4400 rpm's to get my 24 mph's and still get the bennifits of the higher rpm's? Also what will this mean to my fuel consumption. Did I trade fuel and speed for better engine wear and quick ness ?

 

[triumphrick]

Re: prop help?

For some reason that 13 pitch just doesn't sound right. I just repropped and had no way of telling the pitch on the old prop I had, so after sufin a bit I turned up this site and was really surprised. It lets you enter the mo0tor and boat info, the gallons of gas and any extra weight and helps pick two sizes of either stainless or aluminum props. Took the guesswork out and I was able to start pulling about 5200 rpm out of my 85 hp. Here;s the site.


http://www.dansdiscountprops.com/

 

[sburner]

Re: prop help?

For some reason that 13 pitch just doesn't sound right. I just repropped and had no way of telling the pitch on the old prop I had, so after sufin a bit I turned up this site and was really surprised. It lets you enter the mo0tor and boat info, the gallons of gas and any extra weight and helps pick two sizes of either stainless or aluminum props. Took the guesswork out and I was able to start pulling about 5200 rpm out of my 85 hp. Here;s the site.


http://www.dansdiscountprops.com/

Thanks . That is a nice site but it really didn't help me because of the option they gave me. What I really need to know is if I run higher rpms to achieve the same speed , will it be harder on the engine and use more fuel even though it seems to be running smoother and I have a higher top end rpm?