No water pressure
 

My stbd 525 efi does not have any water pressure. Ive replaced the impeller 3 times already this year, th elat time being, the last itme i took the boat out. When a hose is hooked up to flush the engine, pressure is fine. when i dropped the boat in the water and fired it up water came out the exhaust, but no pressure. water soon stopped comeing out (went through what was left in the hose) I have not had to replace my portimpeller once over the past year. My headers are also burnt on my stbd side. What coudl be causeing this? the sea strainer is clean. what is the best way to diagnose my problem?
thanks
-Rick

Re: No water pressure
 

Have you check the fresh water flush hose for a leak or for being tight.Happen to me once the plugs wasn't tight so it was sucking air.

Re: No water pressure
 

Check the front shaft of the raw water pump , I have seen them suck air from the seal there. If there is any play in the shaft this is very possible. Bearings and the seal could be worn. I have seen this quite a few times. Tom

Re: No water pressure
 

Make sure you have reinforced hose from the out-drive to the sea strainer and on to the raw water pump. It could be collapsing under suction or there could be a blockage in the pickup.

Also make sure pulley is tight on the raw water pump

Re: No water pressure
 

check two things, check where the water intake hose come thru the transom on the inside,remove the hose nipple and make sure the hose is not resticted from corrosion, and check the hose between the transom assy and the outer bell hosing make sure not cripped

Re: No water pressure
 

back flush your system, you may have part of your old impeller stuck in the oil cooler???

Re: No water pressure
 

how do i do that?

Re: No water pressure
 

pull the hoses and stick the water hose in the opposite line to push the trash the other way. Been a while since I have done that. I'm sure there is someone on the board with more specifics on the matter.

Re: No water pressure
 

here is a flow chart for your mtr will give you some insight as to what everyone is taliking about :drink: :drink:

Re: No water pressure
 

thanks for all the advice, thats tomorrows project.

Re: No water pressure
 

Don't have a 525 but my 502mag sounds like it had the same problem .- fried 1 engine and melted an aluminum manifold.

Thanks to Joe(goodt) and Stan(cig1988) pointing me to the hose that was all plugged with corrosion. Good with hose in fitting during testing, at lake pickup, Slight water at idle, but under load not enough volume to cool exhaust.
For me, it was the transom hose assy (part #32-43437 and insert 41674) that most recently was my gremlin.

Lostinboston please let us know what fixed your issue.


Stan and Joe, thank you for your help.

Re: No water pressure
 

GoCiggie31,

glad you made out ok, Im shure it was a pain to fix (been there done that) just glad to hear you got it... :evilb: :evilb: :evilb:

Joe

Re: No water pressure
 

On bravo models there could be corrossion in between the collar that holds the water hose on the inside of the transom assy-I have seen corrossion get between the collar and the housing actually turning the collar and restricting water intake flow-you need to take of the 2 -5/16 bolts that holds the fitting onto the inside of the transom assy in order to diagnose correctly.year really doesnt matter -salt water time does

Re: No water pressure
 

wasnt this just said or am I missing something???? :cool: :cool:

Re: No water pressure
 

mr mercruiser ,

welcome to oso sorry didt notice you were new :D :D

Re: No water pressure
 

Changed water impellel but still had low pressure. checked all the hoses and they were fine. Then replaces seal on impeller housing which bumped it up 2psi at idle and 5 at cruise. Hopefully that was it.
Thanks for the advice

Re: No water pressure
 

I hate to admit this but one time I took off the pump to put in impeller and hooked it back to the hose and everything was fine.Put it in the water had some water comming out but not alot.Engine and exhaust got hot,could not figure it out and finally saw that I hooked the hoses on the back of the pump reversed.Switched them and well you can figure out the rest.

Re: No water pressure
 

Glad to see you might have fixed it. Lets us know how things go.

Re: No water pressure
 

Are there any fittings to run SS braid hose from the transom inlet? I have the adaptors that Hardin sells but can't find the fittings.