2003 ox66 225 EFI, Question about water intakes

[KCLOST]

Hello,

I'm having a bit of a problem with my dealer/service in regards to loss of water pressure at WOT..
Let me give you some background info... I purchased this motor with my TR20 of the same year about a month and a half ago. During the test drives we has an overheat alarm come on and the dealer obviously put in a new water pump before I picked it up. Now this boat/motor are new, and have been sitting around for 3 years or so, so that was nice of them...
Anyway, I purchased the boat and started the breakin... Eventually I opened her up and adjusted the motor height. At 6.5" above the transom and a 8" detwiler jackplate I was reaching 75-76mph and showing 5800 rpms with a 27P Tempest. The water pressure was holding steady at 16-17psi. My trim wat at 3/4 up according to the guage... I did this several times and was very happy and everything worked great.

Now hear is the problem... One day a few weeks back I was running at WOT about 1/2 way trimmed out and I looked at the guage and was runnning 20psi. I look ahead and continue for a few seconds and happened to glance at the guage and it is reading ZERO. So I immediately decelerate and I gain water pressure again to 20psi.. I retested this a few times and the same thing happens, It will hold at 20psi for about 10 seconds and then the guage just drops down to nothing. (however I shut it down before that happend again). My dealer says the motor was too high so they lowered it about 3". I go to retest, and the same thing happens. I'm only about 3" above the transom now. Each time this has happened I have not gotten an overheat alarm, which is good! Caught it early enough I guess.

So I take it in again and they now say that I have the wrong water intakes!!!.. Have any of you heard of this? Is there a newer style out there. I still don't understand why everything was fine and now it's a problem...

[JeremyL]

Sounds like it might be some trash in the poppit valve, check the link at the top of this page as to how to clean it out. This might be it but not sure, also could be a falty gauge, have thay checked it out??

[KCLOST]

Trash in the poppet would not cause the water pressure to drop to zero. It would actually cause it the pressure to rise if it can't open and dump water, right..

[JeremyL]

Sometimes it will get stuck open, like I said it was just a thought, dont really know what else could cause it unless it was the guage.

[PF22]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KCLOST &raquo;</TD></TR><TR><TD CLASS="quote">Trash in the poppet would not cause the water pressure to drop to zero. It would actually cause it the pressure to rise if it can't open and dump water, right..</TD></TR></TABLE>

No, if it is stuck open, it will give you a lower than normal reading since it is open all the time and continously dumping water and not letting pressure build up. But this would not cause you to get zero psi. What is your Water Pressure at difference RPM ranges?
Is it the same as in the past?

[KCLOST]

The water pressure is fine until it starts to drop at WOT...
At WOT it will reach up to 20-22 psi and as I run for just a little bit it will start to drop rather quickly all the way down to zero...

At other rpm levels the pressure are normal.... The same as in the past...

[Yellow Jacket]

I have a 2002 Yamaha 225 OX66 that ran flawless for four years. Mine is at the Yamaha Dealer for lack of water pressure at WOT. Sounds like we have the same complaint!!

[GE Blazer]

Actually Yamaha changed the water intakes from 2002 to 2003. Many people had to raise their engines higher on the transom than they could run them with the 2002 models. Everyone was lowering their motors and losing more water pressuer than raising them as they should have been doing.

[KCLOST]

That's interesting, sounds like exactly what I'm dealing with...

[Yellow Jacket]

I stopped at the Yamaha Dealer where my boat is at. The Dealer told me last week they had another 225 Yamaha doing the same thing. After three weeks of trying to fix the problem a Yamaha Rep. came and found the water intakes to be misaligned and put in the new style poppit valve, spring and grommit. So far that has cured the problem. My Dealer has ordered the new valve, spring and grommit for mine. Please let me know what fixes yours.

[KCLOST]

21XL,

Thanks for the imput. Was that motor completely losing water pressure at WOT or was it just below normal?

[Yellow Jacket]

Normal water pressure up to 55mph was at 16-20psi. Above 55mph the water psi would fall to zero quickly. I talked to the Yamaha Dealer again and they said they had double checked the Water Pump and Thermostats. All checked out OK.

[KCLOST]

Thanks,

That is exactly what I'm dealing with except I might be running about 60-65 before the pressure drops....

I'll let you know what happens with the new intakes.... Or whatever else they do..

[Yellow Jacket]

The Dealer has modified the Poppit Valve and removed the TH Marine Hot Shot Plate from the bottom of the TH Marine Jack Plate. I went with the Dealer for a test ride and guess what? No differance. The Dealer will call Yama HAHA in the morning!!

[KCLOST]

I'm begining to wonder if there is a problem with the shape of the lower unit to where at high speeds the water cannot flow smooth enough around and prevents it from entering the intakes... I know this is a big statement and it may not be the case. But it has to be either the design of the intakes the shape of the lower unit or both... Maybe cooler water temps may have an affect, I don't know how it would but is it possible.. Because mine worked fine in the hotter summer periods.

If it's not any of the above, I keep thinking that it's got to be the water pump impeller, but my dealer checked it out and says it is good. And even if it got hot and may have weakened it I would think that wouldn't loose all water pressure, would I? Or see it go from 20psi to zero within a few seconds?


Modified by KCLOST at 12:27 PM 9/29/2006

[Yellow Jacket]

I bought my Boat and Motor Combo four years ago. It has been exceptionally reliable, and has performed excellent just until recently. I did stop by the Yamaha Dealer again today, finally they took the advice I gave them from GE Blazer about the water intake screens. Of course they didn't have the screens in stock so, they had to order them from Yamaha.

Rich

[Yellow Jacket]

KCLOST, If you would to talk about this more E-Mail me your phone # I will call you. lsgueglia@cfl.rr.com

Rich

[KCLOST]

More bad news,

Called the dealer today and they say the boat is ready. They switched the intake screens out with the new design. The have more of a scoop on them but the bottom 1/3 or so is completely flat with no holes of any kind... Don't know why they did that.

Anyway, my service guy said that they took it out for a run and they still saw a drop in water pressure at WOT. So they lowered the motor even "more" and said it held and was good to go.

Now the damn motor is so low that the back of the cowling is about 3" or so under water while idling. I can't even see the tell tail with it trimmed down. While unloading off the trailer I trimmed the motor down until it stopped and tried to back it off and it wouldn't. Low and behold the skeg was pushed against the concrete and my trim guage was still pegged at max up...

So after figuring that out, I take it for a run and it chine walkes like crazy but get it under control and trim out to halfway according to the guage. The same freaking thing happens. With the new intakes I'm running about 15psi at WOT and it just drops to zero after a few seconds.. (those as@#$@#'s). Actually have less water pressure before it drops, it used to read 20psi...
At this point I'm really pissed, and decide to let it run with no water pressure and see what happens. I let it go for 5-7 seconds and the overheat light or alarm never came on, and I turned around (not safe but I did it anyway) and there was water exiting the telltail, but It looked like it may have been spurting somewhat rather than a nice constant stream. Maybe the wind was the cause, it's hard to tell.
Who knows.... They are calling Yamaha and will get the rep in to take a look at it.. But the new intakes didn't work and the motor is lower than hell and that didn't help either... Believe it or not the tech (who has 20yrs experience) says that my boat and motor combo has incredible lift and that is the cause... I again clearly told them that it ran just great with great water pressure with the motor 4"+ higher... They just don't know what is wrong... I'm thinking about replacement already.... The tech said the guage is fine also...

[KCLOST]

Rich,

I sent you an email, actually two of them forgot to add my phone number on the first one...

Layton

[Yellow Jacket]

I stated earlier that I have owned the boat for four years. I should add that I have used the boat either Sat or Sunday every weekend for the last four years without any water pressure issue. To this point the Dealer has installed a new water pump kit, t'stats, removed the Hot Shot Plate, and will try the new poppit valve design next week when the new screens come in. The Yamaha Bulletin in referance to the screens gives an elevated cavitation plate to pad measurement. You may want to mention this it sounds like they lowered the motor on yours.