Quick Yamaha Prop Question

[MMesplay]

Hey guys, I have a quick question. Posted over in the Props Forum but thought someone here may be able to help. I recently purchases a Yamaha 25p T1 for my 2007 Yamaha 200 HP VMAX HPDI. It is currently on its way to its new home from Florida. It is going to replace the Yamaha 23M prop that is currently on my motor. I have verified that the new 25p T1 does not have the pressed-in 2 piece thrust washer. Are these two props totally interchangeable? Will I need any additional hardware to make this swap? Thanks for the help!

[BuzzB8]

It should match right up.

[MMesplay]

That is what I was hoping. Can't wait to try it out this weekend. Hoping to get some more top-end out of my set-up. The 23M just ain't cutting it. Thanks for the info

[dward51]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by MMesplay &raquo;</td></tr><tr><td class="quote">That is what I was hoping. Can't wait to try it out this weekend. Hoping to get some more top-end out of my set-up. The 23M just ain't cutting it. Thanks for the info </td></tr></table>

A 25 pitch will cut your WOT RPM's so unless you can make it up by raising the engine on a jackplate, you may loose top end speed overall. Just make sure the 25 doesn't bring the WOT RPM's below the manufacturer recommended minimum as lugging the engine will build carbon and that is not good for the engine or your check book.

[CStewart]

And if you dont like the way the 25 T-1 runs on your rig, let me know I have been looking for a good used one for a while.

[alh7498]

let me know if you decide to part with the 23M prop...

[dward51]

Dang..... I didn't know we had prop vultures

[PSM207]

There is a big difference between the 23M and the 25 T1. What boat and what's your wot rpm's with the 23?

[21XDC]

More info here&gt;&gt; http://www.bbcboards.net/zerothread?id=554496

[MMesplay]

I have a 2008 Champion 188 with a 2007 Yamaha 200 VMAX HPDI. Currently with the 23M I am turning 5500, but I am really low on the plate. I just purchased this boat about a month ago and just now starting to tweek it a bit. I somewhat have the cart before the horse here, as I need to get a water pressure gauge installed before I go adjusting the motor height. That is in the works. Right now I am roughly 5.5" below pad.

[dward51]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by MMesplay &raquo;</td></tr><tr><td class="quote">I have a 2008 Champion 188 with a 2007 Yamaha 200 VMAX HPDI. Currently with the 23M I am turning 5500, but I am really low on the plate. I just purchased this boat about a month ago and just now starting to tweek it a bit. I somewhat have the cart before the horse here, as I need to get a water pressure gauge installed before I go adjusting the motor height. That is in the works. Right now I am roughly 5.5" below pad.</td></tr></table>

X4 on the pressure gauge before "tweaking" the height.

As to the 5.5" below the pad, that does sound overly deep. However where does the anti-ventilation/anti-cavitation plate hit in the water flow when at WOT & full cruise speeds (with motor trimmed like you usually do at those speeds)? That is an easy point to start at. The water should not be flowing over the plate, but should just be lightly kissing the plate (some spray may flow over). The deeper you bury the lower unit, the more drag and loss of speed you have.

Now with bass boats, a lot of folks will tweak the setting even higher with jack plates and monitoring of the water pressure to get more speed. Height is a trade off between speed and the prop blowing out in certain water conditions or turns, but the plate even with surface of the water at speed is the proven standard for best speed & fuel economy (at least to start with).

Here are two photos of what I'm talking about. The first is a motor that is set too deep (plate is burried in the water column). The second is a motor set at optimum position.

Also here is a good post on the subject at another forum (with more photos)

http://www.veradoclub.com/smf/...137.0

[mark Z21]

I can promise you that the 25t1 will be slower than the 23m (on your boat) if you were bouncing poff the revlimiter, I might try the bigger prop. the T1 is bigger diameter and harder to turn, combined with the increase in pitch .. . . been there, learned the hard way. for example: we just changes out my brothers 25m (5100 rpms) to a smaller 23m (5750rpm) and the boat picked up 3 MPH and hole shot cut in half. you will be able to run the T1 a little higher, but I would start by getting your engine in the right hieght ball park, then using the guys on the props forum to take your RPMs, water pressures, speed and holeshot and can get you into thte right prop range. BTW, my last boat ran 67.8mph with the 23m and a 200HPDI