New member/Prop Advice?

[TexasBoater]

Hi guys I've been a member
for a while, but haven't posted anything. There seems to be a wealth of knowledge here about anything V20 related!
I bought a 1996 V21 last June, I bought it in Florida, but it was a freshwater boat that had spent its life in New York. The previous owner kept it inside and took great care of it. I've been wondering if one of the guys on v20.com might have been the previous owner?
I'm from Texas but I am currently living and boating on the Mississippi Gulf Coast.
Last summer, I didn't really do anything to the boat, but run it as often as I could and take the 3 foot long Wellcraft sticker off the hull!
Before boating season gets going this spring, I've got some projects planned starting with upgrading my prop and adding trim tabs.
I've got a rebuilt 1996 150 hp Johnson Ocean Runner, and as much as I have been enjoying all of the threads about Evinrude E-Tecs. The 200 HO looks awesome! I'm going to have to keep the Ocean Runner, at least for a while.
I thought I had a aluminum prop (mainly because it was painted black) but after getting the part # and doing some research I found out I have a SST stainless steel prop 15x17 I guess it's one of the older stainless steel prop designs?
At wide open throttle two people and some gear on board my top speed is 38 mph and rpms are 4600. Is this a typical prop for a V21 with a 150 hp motor?
Shouldn't I be able to run at 5000 or so rpms wide open throttle?
What size props do you guys run on a similar set up? Anybody running any of the newer stainless props like Vipers or Rebels on a similar setup?
What kind of rpms and speeds are you seeing with 150 horse motor?
Thanks for your help and advice.
I'll try to figure out how to post a few picture of the boat.

[THEFERMANATOR]

your speed sounds good, but i would want to see more rpms out of it. what kind of boating do you primarily do? what do you want from the boat performance wise? these are questions that determine what kind of prop you need. i personally for an offshore/cruiser like the large diameter props. you lose a little top end, but they plane out slower, hold the water tightly, and provide goog mpg's.

[tsubaki]

Welcome to the site!
Before changing the prop, look at the engine setup.
Depending on what performance you want to achieve, raising or lowering the engine on the transom a bolt hole or two can make a lot of difference.
Usually the starting point is to have the cavitation plate even with the bottom of the boat and go up from there. Having the cavitation plate a little over an inch above the bottom of the boat is not uncommon. This will vary greatly with hull design and engine setback. Having one too high will cause overheating and ventilation.
My boat is different than yours, the OAL is 20'6" and I've got a jack plate on it but maybe this thread will give you some ideas.
http://www.wellcraftv20.com/communit...ad.php?t=12543

[spareparts]

make sure your tachometer is accurate, compare it with another tach(tempoary hook up another one) or have a tech use their shop tach to check yours.

[THEFERMANATOR]

Originally Posted by spareparts

make sure your tachometer is accurate, compare it with another tach(tempoary hook up another one) or have a tech use their shop tach to check yours.

I would think he's pretty close(within 200RPM). I know many like the 17 pitch prop for a V-20, but with a 1.86:1 lower it is an awful lot of pitch for a 150 to spin. If it was a 2.0L MERC with a 2:1, it would be dead on, or if it was a 200+ it would be fine. For a 150 though I think he needs to drop back to a 15 pitch prop. His current numbers put him at roughly 5% prop slip, so it sounds like the engine may be a tad to deep on the transom. And the easiest way to check if the engine is mounted correctly is go out and run it. While at WOT go back and look at the anti cavitation plate(it's best to have somebody else drive instead of leaving her unattended) and see if it is under the water, even or out of the water. For best performance you want it to be just out of the water at WOT.

[macojoe]

I use to run a 15 pitch I liked the performance much better, tad slower top end but better every where else.