Raw water pump installation

[Trojanman]

Morning Gents (and ladies). I removed my raw water pumps back in the fall to do impellers. Now I'm putting them back together and can't remember which way they go?? This pic is my Starboard motor,(right hand rotation) it made sense to me to have the intake and output ports facing towards the left, as you know the ports are not in the middle, this way with the motor turning clockwise it would suck up raw water from the bottom.I did the exact opposite to the Port motor, turing the housing so the ports are facing towards the right (if that makes any sense?) Please tell me if this correct I don't want to start it with it being in wrong.

[RicardoMarine]

The orientation of the pump shown would be correct for a Standard LH Rotation Engine... not a Reverse RH Rotation Engine.



Typically the Port engine will be a Standard LH Rotation (same as car/truck engine), and the Stbd engine will be a Reverse RH Rotation.

These are always viewed as if looking at the flywheel end.

This is a Standard LH Rotation Marine Engine.
Looking at the sea water pump from the front of the engine, the pump would rotate CW.


This is a Non-Standard RH Rotation Marine Engine..... aka Counter Rotation.
Looking at the sea water pump from the front of the engine, the pump would rotate CCW.


This may appear to be counterintuitive, but the pump shown to the left would be correctly positioned for the Standard LH engine.... and the pump to the right would be for the RH Reverse engine.

[Trojanman]

So Rick, from what you're telling me, the pump shown needs to be flipped? again..this is my Starboard engine.

[RicardoMarine]

BTW, the cam screw is what tells me the orientation of this pump, and that it needs to rotate CW (viewed from front) in order to work with the inlet below, and with the outlet above.
Flit this pump 180* and it will be correct for CCW rotation (viewed from front).

So Rick, from what you're telling me, the pump shown needs to be flipped? again..this is my Starboard engine.

If your Stbd engine is most likely a counter-rotating engine... I.E. RH Reverse Rotation like this........... correct?


If so, then your Sherwood pump will be in this orientation when viewed from the front.
(inlet/outlet ports to the left..... impeller off to the right side turning in a couner-clockwise direction)





************************

This is not your pump (below), but is in the same orientation as our RH Engine pump's impellers.
It is turning CCW when viewed from the front of the engine.
Look at the action as the impeller rotates CCW.
This is the "counterintuitive" part at first glance.

The vanes are just leaving the cam and are just opening from the cam action.
As the space between the vanes becomes larger, suction is created, and it pulls in sea water.
As the space between the vanes becomes smaller (from cam action at the other end), the sea water is forced into the outlet and on to the engine.



OK... switch gears for a moment, as I do not have an image for a RH Reverse engine pump.
This is a Sd LH Engine Sherwood pump (below) as though viewed from the front of the engine.
The blue area shows incoming sea water..... the yellow area shows the outgoing sea water as it's being compressed by the folding action of the vanes via the cam.
Again.... this Sherwood is for a Sd LH Rotation engine.... just think of this as though you are looking at a mirror image for a Rev RH Rotation.

[Trojanman]

Got it, Thanks Rick. Love the pictures, so detailed I love it!! Next time I'll take pics when I take something apart. That'll teach me.

[RicardoMarine]

Got it, Thanks Rick. Love the pictures, so detailed I love it!! Next time I'll take pics when I take something apart. That'll teach me.

You are welcome.
Doubt that you'll need pics...... once this is understood, you won't forget it!

BTW, final exams are on Friday!

Have fun!

.

[Trojanman]

[pete31]

I have a red pump & a green pump...went through to many impellers

[Trojanman]

What did we do before boat forums? All these smart machanics were safe from us. Now there's no where to hide !

[fastjeff]

Hee, hee!

Jeff