2003 ox66 225 EFI, Question about water intakes

[BuzzB8]

WOW, most hammer owners see an increase in water pressure once they raise the engine. Put it back where it was at the beginning and try it.

Your trim sending tab is probably broke. They break often, but are cheap to fix. I think I got two of them for under $6. Here's a picture of where to find the broken piece.

[KCLOST]

No the trim sender tab is not broke, they just replaced it a few weeks ago...

The motor is just that low...

Took it out again today with a 25M Yamaha prop. Same thing happened, lost water pressure after running at WOT for about 5 seconds and 1/4 trim according to the guage. I decided to raise the motor up as far as it would go which ended up being 5.5" above the transom... It ran better, at least it held pressure at about 11 psi at 1/2 trim but it still lost pressure with more trim...
I have totally gotten on the bad side with my dealer. They just think I want to run the motor too high, they still don't get that the freakin motor won't take in water!!! Had a sit down with them today and the service manager was just being an a$$.. But the owner was at least somewhat supportive...

I did get an overheat alarm today while I was decelerating and making a turn... But while running straight and the guage reading zero psi, I have not gotten an overheat alarm.

[KCLOST]

Buzz,

Can you take a pic of your water intakes for me and post them, and if it's not "more" trouble for you can you tell me where your propshaft is in relation to the bottom of the hull...

Right now I can't measure mine because the damn motor won't drop level with the hull before it hits the ground while it is on the trailer... (my dealer set-up)

[BuzzB8]

Mine is 2.75" below the pad. My wp is fine. Also, the pictures on this link don't show my intakes, but they are the original screens and not the scoops. (No need to fix what isn't broken)

http://www.bbcboards.net/zerothread?id=65514

Have they checked the impeller to make sure it isn't turning ON the shaft? Another thought, check the water jacket bolts on the back of the engine between the heads. They've been known to get loose...but you would probably see the water running out from the bottom of the lower cowl.

[Yellow Jacket]

KCLOST
I called you last night and left a message on your phone. Sounds like you were out on the boat. OK, now you tried the new style intake screens and raised the motor back up? Has the Dealer changed the poppit valve? Hey, just asking mine has been modified by the Dealer. It has not been replaced with the new style valve, spring and grommit. I beleive that's next. Do you have the Y.E.S. extended warranty? I do and I feel that this low pressure issue is Yamaha's problem 100% My boat is still at the Dealer, this is almost two weeks now. Tomorrow morning I will calll Yamaha myself and get involved. Last time I had a Trim and Tilt unit failure. Yamaha replaced it which was great but, the boat was at the Dealer for 1 month. That was unacceptable!!

[kk4iz]

Have you had your prop worked yet? IF not let Mark work it ,my water pressure came up on both of my props. I'm running 25 psi at wot jacked up all the way on my hyd jack plate, trim at 3/4 or better. Before we ours worked it was running about 12 or 15 psi.

[KCLOST]

kk4,
It's a "complete" loss of water pressure at WOT... It was not that way a few weeks ago... I don't have the low water pickup like you do..

It's not a motor height issue as we have lowered it all the way and the water pump has been replaced, I also have the new style water intakes with the scoops on them. Nothing has made a difference. Tried both a Tempest 27p and a Yamaha 25M no difference. Poppet valve is not the issue, as a bad poppet would not cause the pressure to drop to zero at WOT. T-stats would not be the cause either even if they didn't work.

Either water is just bypassing the intakes somehow, or something is going on with the water tube. Possibly coming loose or a seal popping out????? And then it re-seats itself when lowering rpm again.

I talked with Rich (21XL PRO STAR) yesterday and we have exactly the same problem. On both of our issues we have Yamaha looking into it and working with our dealer.

[KCLOST]

The dealer called me this morting. Said he talked to Yamaha and also a tech set-up guy that he knows from another dealer.

The next step is to put in another style of intake screens. They are specially designed for the Yamaha motor that is mounted on a Triton hull.
???????
They still say it is sucking in air.. If that's true there is something going on with the pressure wave behind the hull that doesn't work well with a Yamaha lower unit at high speeds. Because they had the motor so low that it is impossible that they were exposed to air.
I'll believe it's fixed when I see it....


Modified by KCLOST at 12:38 PM 10/3/2006

[KCLOST]

Well it's working again...

They ended up putting in the newer-newer style intakes and have the motor 6.75" above the transom... Holds at 23psi at WOT...

[BuzzB8]

That's good news.

[5 keepers]

A buddy of mine had a similar experience. He needed to replace the entire water pump, including the housing and plate. That solved his problem. If they problem returns, you might try that.

[Yellow Jacket]

Mine is fixed too. New style intake screens and jacked the motor way up. Dealer also changed the style poppit valve (mushroom shape), spring and grommit. The boat now runs 75.5 mph on GPS @ 6,000 RPM. That is the fastest for me so far.

[utfisherman]

I think your water pump impeller is slipping on the shaft at high rpm. My 250 ox66 did the same thing last spring. I first noticed momentary drops in psi but attributed it to air intake in rough water. On the next trip I took off after the second stop and opened her up. After 2 minutes I get overheat alarms and noticed no water pressure. After about 1 hour to cool off, I restarted and got a good pee stream. I idled around, then slowly got on plane. Once I was within trolling motor distance of the ramp, I opened her up again and suddenly no water pressure. I was able to repeat this 5 times, losing pressure above 4000 rpm. The mechanic could not find any problem on tear down, but replaced the impeller, housing, and gaskets anyway. He warned me about running the engine too high (but he is a Skeeter mechanic, so what does he know about Stratos setup?), but I've never had a problem before. Everything has worked great since. He mentioned something about differenct intake screens if needed, but I never bothered.

[21XDC]

Rich... I'd like to get a new screen for mine... How do I know what one tom get? and How much do they cost? I may have a new one now, Just making sure.

[KCLOST]

21XDC,

If you have the low water pickup like on the HPDI's, I have no idea if and what you might need...

The ones I got are direct from the Yamaha Testing center, and they were specifically designed for a Triton Hull... They are a little different than the ones Rich has on his motor. They tried those on mine first and it still didn't help. Makes you wonder why they would have to design intakes for a specific hull. You won't find a part number for them, at least I haven't been able to.

There is obviously something wrong with the lower unit design at high speeds. This is not a motor height issue as we had my motor as low as it would go and it still lost pressure, and they also changed the water pump out twice...

I still believe that there is a problem with how the water flows around the lower unit.. My yamaha 225 lower unit in my opinion is one of the bulkiest, un-streamlined units I have ever seen.. My old Merc. 175 Black Max had more hydrodymanic contours compared to this Yamaha......

With certain Hulls I believe it creates so much of a pressure wave infront of the cone that water flow is disrupted from flowing smoothly into the intake screens.. Why have they designed new ones more than once? The funny thing is, Yamaha will not say in anyway that there is a problem, but they will offer you the new style intakes without charge and be almost willing and happy to do it...

[Yellow Jacket]

I can e-mail some pictures if needed.