'95 3.0LX - Water Pump Question

[BeeEl]

Hello again. I have been tying up all the loose ends on this boat. Finally got around to asking this question that is a little puzzling for me.
This is a 95 3.0LX with Alpha One.
I occasionally put the drive in a tub of water and run it for a while just to keep it happy. I notice when I do this, the impeller pumps water up into the engine (I am sure of it because I felt for the suction). There is no water coming out of the exhaust bellows for several minutes. I noticed that once the temperature gauge climbs up to a certain point (can't remember exactly where) I finally get water coming out of the exhaust. The temperature goes back down to almost zero and stays there. The water will continue to come out of the exhaust as long as it is running. So is this normal? Hanging thermostat?
This almost cant be normal because the manifold/riser or whatever it's called has got to be incredibly hot and then dumping water through it can not be a good thing.
I get about 80% of the water out of the right side port. The rest comes out of the left. Is this normal? I don't recall why there are even two sides when there are only 4 cylinders inline.
But the weirdest thing - while I am waiting for the water to start pumping out, there is a constant rattle coming from those ports. Almost sounds like bells ringing around in there. As soon as the water starts flowing, it goes away. Any help would be greatly appreciated as I have no one within about 80 miles that will even look at it - not to mention I enjoy the DIY aspect, but don't want to ruin stuff due to sheer ignorance. I can take a video if that would help.
Thank you in advance for any advice,
BL

 

[alldodge]

Re: '95 3.0LX - Water Pump Question

Hello again. I have been tying up all the loose ends on this boat. Finally got around to asking this question that is a little puzzling for me.
This is a 95 3.0LX with Alpha One.
I occasionally put the drive in a tub of water and run it for a while just to keep it happy. I notice when I do this, the impeller pumps water up into the engine (I am sure of it because I felt for the suction). There is no water coming out of the exhaust bellows for several minutes. I noticed that once the temperature gauge climbs up to a certain point (can't remember exactly where) I finally get water coming out of the exhaust. The temperature goes back down to almost zero and stays there. The water will continue to come out of the exhaust as long as it is running. So is this normal? Hanging thermostat?
This almost cant be normal because the manifold/riser or whatever it's called has got to be incredibly hot and then dumping water through it can not be a good thing.
I get about 80% of the water out of the right side port. The rest comes out of the left. Is this normal? I don't recall why there are even two sides when there are only 4 cylinders inline.
But the weirdest thing - while I am waiting for the water to start pumping out, there is a constant rattle coming from those ports. Almost sounds like bells ringing around in there. As soon as the water starts flowing, it goes away. Any help would be greatly appreciated as I have no one within about 80 miles that will even look at it - not to mention I enjoy the DIY aspect, but don't want to ruin stuff due to sheer ignorance. I can take a video if that would help.
Thank you in advance for any advice,
BL

Using a tub is not a good thing, you should be using muffs. The impeller should be able to suck the water out of the tub but normally the water is higher so the lift is not as much. How old is the impeller? It would take some time for the water to start going through the exhaust but this should not be that long. If the engine was dry it might take 30 seconds. Check your thermostat housing and see if something is clogged up. There should be a bypass which allows water to go to the exhaust without coming out of the engine block.

 

[Bondo]

Re: '95 3.0LX - Water Pump Question

Ayuh,.... I Agree with AllDodge,... Yer ruinin' the impeller tryin' to run it in a bucket,....

The pump is a flooded impeller pump, which needs to be completely submerged,...
The muffs force feed it, makin' it think it's Flooded,...

The bells yer hearin' are probably the burnt shutters rattlin',...

 

[BeeEl]

Re: '95 3.0LX - Water Pump Question

Sorry, the impeller is brand new. Came on the new lower unit. The impeller is completely submerged - it's actually the bottom of a 55 gallon drum. I thought that would work better than muffs, but I'm glad I asked. I will put the muffs on.
There must be a bypass clogged. I'll check the housing. The confusing piece is why does it continue pumping once it starts? If there is a clogged bypass, I can see why it would wait for the thermostat to open, but I what makes it stay open? I would think the thermostat would open and close in an effort to maintain temp.
By burnt shutters, do you mean valves? As in exhaust valves?
And what about the water coming from once side way more than the other?
Thanks again

 

[Bondo]

Re: '95 3.0LX - Water Pump Question

Sorry, the impeller is brand new. Came on the new lower unit. The impeller is completely submerged - it's actually the bottom of a 55 gallon drum. I thought that would work better than muffs, but I'm glad I asked. I will put the muffs on.
There must be a bypass clogged. I'll check the housing. The confusing piece is why does it continue pumping once it starts? If there is a clogged bypass, I can see why it would wait for the thermostat to open, but I what makes it stay open? I would think the thermostat would open and close in an effort to maintain temp.
By burnt shutters, do you mean valves? As in exhaust valves?
And what about the water coming from once side way more than the other?
Thanks again

Ayuh,.... Was the old impeller, Complete, no missin' pieces,..??

Missin' pieces could get to the t-stat housin',...

The exhaust shutter stops water from backwashin' into the motor,...
They live at the top of the down-pipe, 'n burn up with no water flow,...
Pieces of 'em coulda fallin' down, 'n cause the disruption of the exhaust water flow,...

 

[alldodge]

Re: '95 3.0LX - Water Pump Question

The impeller is struggling to get water up thru the engine so this is why it takes the thermostat to open before you get water out the exhaust (stat opens less restriction). Could be your engine has over heated the water which keeps the stat open (just guessing). The shutters are in the exhaust tube, they are also called flappers. As Bondo mentioned they are getting hot, probably metal type which ring as the exhaust passes without water.

Don't bother with which side has more water coming out more, this is just water finding the path of least resistance

Edit: Need to shorten my message so it doesn't take so long to type

 

[BeeEl]

Re: '95 3.0LX - Water Pump Question

I replaced the entire lower unit, not just the impeller so I don't know what shape the old one was in. I'll find out tonight.
I bet you are right, that is probably what is causing the water to flow out one side more.
I guess I'll see if I can get them pulled apart .
Thank you so much

 

[smassey22180]

Re: '95 3.0LX - Water Pump Question

I have a 95 3.0 and I also get 80% of the water out the right side so that is normal. I think the 3.0 only has one shutter. Most of the water bounces off the curve of the pipe and then falls down. Since it only comes from one side it is not even like a V engine.

http://www.mercruiserparts.com/Show...8.png&inbr=1604&bnbr=190&bdesc=Exhaust+System

If I start mine on mufs I get water out the transom within a few seconds. You should remove your thermostat and see what is going on. When I got my boat last year the thermostat was pretty corroded and clogging things up.

 

[BeeEl]

Re: '95 3.0LX - Water Pump Question

I checked it out last night. The thermostat is actually stuck open. I should say was. After disassembly and some cleanup, it functions great now. This would explain the water continually pumping out and the temp staying all the way down (after the initial delay). I am just hoping the reason I wasn't getting water for a while was because I was using a bucket instead of muffs and that's what was taking so long.

 

[Volphin]

Re: '95 3.0LX - Water Pump Question

I checked it out last night. The thermostat is actually stuck open. I should say was. After disassembly and some cleanup, it functions great now. This would explain the water continually pumping out and the temp staying all the way down (after the initial delay). I am just hoping the reason I wasn't getting water for a while was because I was using a bucket instead of muffs and that's what was taking so long.

At least it didn't fail closed like the old days...