impeller direction of rotation.

[rickinnj]

I'm in the process of rebuilding my oberdorfer raw water pump and was wondering which direction the pump spins when installed. I want the vanes to be pointing in the right direction from the get-go. Let's use facing from the cover plate as a point of reference. With my luck, this is answered in the directions...I haven't opened the box yet.

Rick Bushie
s/v Anchovy, 1971 C&C 30-1
Worton, MD

[thatch]

"Righty Pumpy"

Rick,
The impeller rotates clockwise when viewed from the plate end (same as engine rotation). I normally lube my impellers with some Vasaline or lithium grease which seems to help the initial priming and keeps the vanes from "scuffing" when dry.
Tom

[Kurt]

Yes - it rotates clockwise, but I don't believe it is necessary to "point the impeller vanes in the right direction". I often wondered this myself when rebuilding water pumps. If you think about it, those vanes are flexible so they will orient themselves when the impeller starts spinning. I do use a thin coat of lith grease in the impeller chamber when rebuilding pumps and doing routine maintenance myself as well.

[rickinnj]

Thanx.

I figured that I may as well configure them right in the first place to eliminate any undue stress.

[JOHN COOKSON]

Same as Kurt

Thanx.

I figured that I may as well configure them right in the first place to eliminate any undue stress.

I don't think it matters. When you crank the engine the impeller vanes will orient themselves before full engine torque comes along when the engine starts.

I lube my new impellers with a small amount of lithium grease and prime the pump by pouring a few cupfuls of water down the inlet hose (tape the hose upright), turning the engine over with the hand crank to to get rid of bubbles, then more water down the inlet hose before hooking on to the through hull.

Turning the engine with the hand crank orients the vanes.

Just my way I guess.

TRUE GRIT

[sailbristol]

they do not

before I switched to fresh water cooling I flushed the engine with full pressure garden hose attached to water intake then I ran muriatice acid bath through engine out of a bucket when I took the pump apart after this to change fittings the vane on the impeller where going the wrong way the water hose pressure had disoriented them

[BryanLee]

It's my understanding (which is not always correct) that an engine can kick backwards at times anyway, not a full turn, but a bit. For instance, when shutting down, if a piston is coming up on a compression stroke, but then the others are no longer firing the compression will force the piston back down, reversing the engine for just a little ways. My understanding is this will flip the vanes the wrong direction anyway, that is why they are flexible enough not to be damaged if they get flipped.

Please correct me if this is not correct.

Thanks,
Bryan