Water Pressure 2003 ox66 3.1L

I have a 200 hp 3.1L that runs 15-16lbs of pressure at mid range speed. When I run at WOT the pressure is dropping down to 11-12lbs of pressure. The prop to pad is 3.5 below pad and the lower unit is new with 8 hours on it. My experience in previous boats is the water pressure is at its highest at WOT. The motor is not overheating but I am concerned about the low pressure @ WOT. I have ordered new water inlets (61A-45214-11-00 & 61A-45215-11-00) for the lower unit, as the ones currently on it (61A-45214-30-00 & 61A-45215-30-00) are the newer style and seem to be more restrictive than the water inlets used on this motor in the past. Any information or opinions would be greatly appreciated.

Did you check the poppet valve yet? A little sand or weeds could be partially opening it and letting the pressure bypass the system.

I have not checked the poppet valve. I feel like the poppet should be fine since the pressure is at 15-16lbs at mid-range speeds. A yamaha dealer told me the motor would over heat at idle if the poppet was clogged.

At WOT I would think the poppet would be allowing the max amount of water though it. It is my understanding if you are overheating at idle, the poppet may be the cause, but not at WOT.

Just to clarify, the motor is not over heating @ WOT, but the pressure does drop to around 11lbs.

Are you over-trimmed or under-trimmed at WOT? My water pressure is sensitive to over-trimming and is highest when I am running correctly. Under-trimming also lowers the pressure a few pounds. Otherwise, also check the thermostats on top of the engine (debris collects there). Good luck.

My 3.1 225 runs 20 psi at wot 5700 rpm. Just a grain of sand under the popit valve will give you just what you have. You should have the new popit valve in it but I would check it. I had this problem over and over until I put in the new valve new spring and new seal. My engine never over heated at idle when this was a problem.

Thank you Hooken203 for the information. I pulled the poppit off this morning and there was one small pebble between the pottit and the seal. I will try the boat out this weekend and report back with an update on the water pressure. I did notice the motor still has the old style poppit and seal. I guess I will replace the poppit with the new style in the very near future.
Thanks!
Phil

I had the same problem and replace popit with the new style and still have the same problem. Water pump impler was also replaced.

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by vorvon46 &raquo;</td></tr><tr><td class="quote">I had the same problem and replace popit with the new style and still have the same problem. Water pump impler was also replaced.</td></tr></table>

I did the same thing, then a guy named Texas Larry on here, told me to check the poppit again, that the round plastic end can get cocked on the rubber seat when you put it back in and cause the same problem as sand or gravel in the valve. Sure enough when I pull it back off, you could see a grove in the poppit valve rubber seat that show it did not seat right when I installed it back in. So if you are have the same problem, you might look to see if it is seated right and not cocked to one side.

This past week I cleaned the poppit valve and also installed the older style "water inlets" on my lower unit. I took the boat to the lake last night and the boat now runs 20psi @ mid range and 22psi WOT. The water inlets I installed allow much more water through than the previous inlets, and I'm sure cleaning the poppit made a difference as well. I want to thank everyone who posted, as all the information was very helpful.
Phillip

You have a part number for the older style water inlets??? Do they mount the same way as these new ones?

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by rangerguy &raquo;</td></tr><tr><td class="quote">You have a part number for the older style water inlets??? Do they mount the same way as these new ones?</td></tr></table>

I would also be interested in that myself

The part numbers are 61A-45214-11-00 & 61A-45215-11-00. These water inlet covers bolt on just like the newer ones do, and let much more water flow through the inlet. The water inlet covers I just installed are identical to the ones on my previous 3.1L (2000 model). I hope this information helps.
Phillip

Thanks Phillip for the part numbers. I'm going to order me a set and see if I can get my water pressure up a little. http://www.bassboatcentral.com/smileys/thumbsup2.gif

2003 models had the change of the water inlets. Everyone thought they need to lower their motors to get the water pressure. Actually, you had to raise the motor. I set up several boats then that had this problem and by raising the motor it cured it. You did the best thing by putting the old style inlest on there.

Exactly, Greg. http://www.bassboatcentral.com/smileys/thumbsup2.gif

I'm about 2.75 below the pad and have never had issues with water pressure. When I first added the jackplate, I started at 3.5 below and the water pressure was about 16. Ever since I did the fine tuning, it's been at 20 or better most of the time.

How much were the new water inlets?