Water Pressure Problem

[GA2]

I had recently posted a question about an alarm and low water pressue 1.4 @2500 rpm in neutral. my boat is a 2006 260 Sundancer 6.2 Merc. Bravo 3.. 77 hours on it. well i rebuilt the raw water pump. the old one was still plyable with some wear marks on it. used plenty of liquid soap to assemble, i took a hose off at the riser , ran a hose in it to fill the system, so it wouldnt start dry. when i started it the pressure was very high about 18.. as it warmed up the pressure began to drop until it was at 0. the engine temp never went higher then 160. i let it cool down and restarted again the water pressure was at 0. tried to race it up in neutral the pressue stayed at 0. when i rebuilt the water pump i noticed the pump cover had grooves in it from the impellar, would the pressure drop from this ? or could there be a restriction at the water pick up holes in the outdrive. or could it be a faulty sensor. its odd how as it warms up it looses pressure. any help would be greatly appreciated.. thankyou. George

 

[Morpheus]

I've had my water pressure sensor and pitot sensor replaced 5 times this week and they still don't work (they would work for a few minutes and then go dead) MM now has the boat and will be trying to figure out what the problem is. This was after they did a 2 year service. Maybe it's not your pump or impeller but the sensor itself.

 

[GA2]

thanks, you might be right. now to find an authorized merc. warranty mechanic that i would trust. good luck with yours.

 

[boughtabouy]

Mine had a faulty water pressure sensor on one of the 5.0's with only 10 hours on it. I think it's pretty common.

 

[flflatrate]

if you are having a problem with low water pressure on your boat, when your boat is a few years old and it is a bravo application and you use it in salt water, the problem is not your pump or your water pressure sensor. It is your transom assembly. I do about 2 of these a month. If you take the plastic fitting off of the transom assy that the red hose goes to from the water pump you will see that the hose is crushed up restricting your water flow. the fitting has 2 bolts holding it on that you use a 7/16 wrench to remove it. after removal you should be able to stick your pinky in the hole. What happens is when you pull the boat out of the water there is salt water between the transom assy and the hose that runs thru it. When that water dries the salt will crystalize. And after a few years it will continue to squease that hose and waaallllaaaa!

 

[GA2]

thanks so much!! ill check it

 

[GA2]

can i do this in the water ?

 

[Morpheus]

if you are having a problem with low water pressure on your boat, when your boat is a few years old and it is a bravo application and you use it in salt water, the problem is not your pump or your water pressure sensor. It is your transom assembly. I do about 2 of these a month. If you take the plastic fitting off of the transom assy that the red hose goes to from the water pump you will see that the hose is crushed up restricting your water flow. the fitting has 2 bolts holding it on that you use a 7/16 wrench to remove it. after removal you should be able to stick your pinky in the hole. What happens is when you pull the boat out of the water there is salt water between the transom assy and the hose that runs thru it. When that water dries the salt will crystalize. And after a few years it will continue to squease that hose and waaallllaaaa!

I should of mentioned this but in another thread I talk about at my 2yr/200hr service I had this exact problem. The tech found exactly what is explained here that the tube was partially crushed from the salt build up and they even found corrosion on the transom plate and had to replace the plate under the 3yr corrosion gurantee. The tech said they are seeing A LOT of this and have had to replace atleast a half dozen in the last few weeks for the exact same problem.

 

[GA2]

thanks again, im going to check it this weekend.

 

[GA2]

thanks to all that replyed, being it was under warranty a sea ray tech came down today. it was a sensor sand gets in it and thats it..............

 

[Morpheus]

Glad it was the sensor. I've been told Mercury is releasing new sensors I'm in line to get some of these since mine keep failing.

 

[petern]

where is the sensor located?