water presure

[wheats]

My mech on my boat is doing a pressure test on the water from the jet pump{circulating engine}.. Is this something that can be greatly reduced if the wear ring and impeller are alittle worn? Water does come out of pee hole, not so much at idle but a firm stream while on the move.. thanks.

 

[Dr Honda]

Yes and no.

Yes... the pressure can be reduced with wear. BUT... if you had enough wear in the pump to keep the engine from being cooled... then the cavitation would be so bad, that you wouldn't be moving.


As far as the flow out the pee hole. At idle... if there is any water coming out... you are fine.


OK... that answers your questions... but why are you paying a Tech to check it? What's the problem?

 

[wheats]

The tech is just about finished with the rebuild.. There not charging for it(pressure check)..It seems he wants to see a certain pressure range before handing it off to me...And im just hoping not to need to replace impeller/ring..

 

[Dr Honda]

OK... it's from a rebuild.

There is a pressure range in the manual... but low pressure could also be from a partly blocked intake. But... as I was saying... if it's coming out the pee hole at idle, you are fine.

 

[wheats]

Very rarely at idle..Always while moving..Crossing fingers its partially blocked.. thanks for your help..

 

[Dr Honda]

The guy should have blown though the cooling system, in the housing... before putting in the new engine. (to clear the feed hose and pickup)

I just rebuild my Islandia... and I get a nice stream from the pee hole even at idle. Oh... idle water also depends on the idle RPM. These Merc boats like 1000 RPM's. If it's down around 800 RPM's... the cooling water at idle will be minimal.

 

[wheats]

You mentioned "at idle" you get a nice stream...Do you get that stream when your flushing too? Oh..my engine idles at 1100

 

[Dr Honda]

1100 RPM is perfect.

As far as getting water out of it while flushing... that depends on the water volume from your garden hose. it has NOTHING to do with the engine, and it's health.

I can't run my islandia on the hose from my garage. There isn't enough volume to feed the engine. It all goes out the pump.

 

[wheats]

I see..so what do you do to flush it out?... Im sure my hose is inadequate also

 

[Dr Honda]

I generally don't flush my water toys. There's no need since I'm running in fresh water. But... I will give them a quick flush at the end of the season.

I discovered the issue with Mercury flushing after I did my rebuild. I knew that the feed hose was wide open, and gravity would do it's job. But... when I started the engine on the hose... my engine was getting hot to the touch, so I knew there wasn't any water getting up into my engine. So... I had to run a biger hose over to a real water spigot from the side of my house.

 

[wheats]

Okay thanks. I'm 10 min from the gulf and what some guys do out here is after a day in saltwater they'll drop it in one of our nearby lakes to flush out.