04 Ranger 521 w/VMax250 OX66, Low H2O Pressure

[QUEDOG521]

Need some help, if I did it right, the engine is 3.5 below the pad. I have checked the poppet valve, no problem there, I have replaced the water pump assemble, assuming it is done right, checked the inlet screens, no problems there and can't get more than 8 to 10 p.s.i. when trimmed at W.O.T. Use to run hot while idling more that 7 to 10 minutes, then I replaced the water pump, that problem solved. Now steering is kinda hard at high speeds, could this be caused by the engine being too high?? The engine was 4 1/8 below and I still had the pressure problem, I read on this board that Yammie's like to run high for better pressure so I took it up to present 3.5 below the pad. My next move will be to go down to 4.5 below to see if the pressure increases and steering gets easier. The only thing I haven't tried is to replace the thermostats. Help me guys, anybody have had my problems?? Thanks in advance!!

[KCLOST]

Ask your dealer for a kit called the "dynamic inlet screens"... This will give you the best water pressure for that lower unit. (with an OX66 it should not be a low water pickup).

This is a good option assuming the water pump, poppet, and everything else related to the cooling sytem in regards to pressure is operational.

[QUEDOG521]

Thanks KCOST! I will get this kit, and give it a try.

[KCLOST]

I had a drastic problem with a brand new Triton that had a 225 OX66, where the water pressure would drop to zero at WOT and trimmed out a little. This started about 2 months after I bought the rig... The dealer tried everything, water pump, motor height adjustments, poppet, etc. It turned out to be a turbulence problem with the interaction with the lower unit. Air pockets would form around the inlet screens preventing adequate water flow into the engine.
My new screens now give me 20-25psi at WOT with the propshaft to pad measurement at 2" below... For some reason it starts with even rigs that have been opporating for a while... I know of two guys, one with a Statos and another with a Triton with this same problem... (again assuming everything else is in working order this should fix it).

And yes running your motor higher will cause more steering torque, but you will go "faster"

Good luck and let us know what happens. It should only cost you less than 5 bucks for the screens. And I wouldn't be surprised if Yamaha picks up the tab... This is a Yamaha design problem btw...

[Trent_in_BG]

where can you find them on the web? I need to see a picture to see if I already have them on.

[QUEDOG521]

I need help.....is this a Yamaha part or is it made by some other manufactuer? If it is a Yammie part can you give me a part number because I called three dealers and they didn't have a clue. Thanks!

[KCLOST]

The part# is 90891-40410-00 Dynamic Inlet Kit 200-250hp OX66 motors only...
Here is a pic of them... Quite different from the ones that were originally on my motor..
[img]http://groups.msn.com/_Secure/0WAAsHfkaGqluQErINalA2be40mRpJj18XvHHwBLGKERN8hDSX jmwRRLvKGbbZrg9wTo7u*1dsw8h2kPe7ZXHsfFyaLOjECW97Ce iDZN89DjcI3lRd1vkdsZ1uXaTYjTkRwAAAP****8/P?dc=4675626573123442199[/img]

You will have to order these from Yamaha, your dealer probably won't have any info on them... My dealer had to order them from Yamaha directly as they didn't even know they existed... They cost $6.50 or so...

You can see on the pic that the screen has a built up area on the top to prevent the air pocket, and if your current screens are like my old ones, they don't have any vents on the bottom section. You can see an old cavitation burn on the paint behind my screen that was caused by the air pockets with the old screens. Since these were installed no further problems or additional burns on the paint.