Atomic 4 overheating update

[Petro206]

Hello all,

So per my last thread, I tried a few things based on your responses (thank you).

Added a Groco Sea Screen.
Swapped out all hoses from Thru-hull up to water pump.

Started her up and she's still not getting water coming out the aft port and thus she begins to get too hot too soon.
The Sea Screen fills with a darker water as if the water is going in the wrong direction. Then I looked on the Moyer site and noticed the fins of the impeller are pointing in the opposite direction as ours.

Image 1 is off the Moyer site.
Image 2 is our last impeller that lasted only a few months.
Image 3 is the newest replacement that isn't working at all.

Is it possible that this opposite direction per installation is causing the water to back up and/or tearing up these blades?

 

[Christian Williams]

Can you confirm that the impeller is actually spinning?

On my M25 Oberdorfer, it was possible when installing the pump on the engine block that the shaft to the engine did not mate. I had to get it inserted just right, and there was a separate spacer/connecter required. The only proof the impeller wasn't turning was lack of water in the exhaust.

That looks like an older Oberdorfer, with grease cup. It might have the same eccentricity mine did.

The subscript on this photo seems to relate to the issue of shaft connection.

 

[Christian Williams]

Petro's original thread on this topic (it's better to add to an existing thread when updating) :

Atomic 4 overheating

Hey y'all, Ok, so I have a 1978 E34 moored in salt water. We've replaced the carb, oil filter, water separator, impeller, hoses, and much much more. We have it all dialed in when idling at the dock. Spits water normally and hums right along. We took her out of the slip recently and I noticed...

ericsonyachts.org

 

[Prairie Schooner]

Is it possible the person who made the Moyer website flipped the image?

 

[Christian Williams]

Looks like the vanes bend left. Not sure it matters how the install is, as I think the rubber would adjust.

https://www.marine-j.com/pdf/Jabsco-impeller.pdf

What I'd do is close the seacock, take the face plate off the Oberdorfer, and turn over the engine to confirm rotation of impeller.

Then I might put the plate back on, open the seacock, remove the output hose and start the engine briefly, expecting water in my face (despite holding up a bucket).

I'd reconfirm that the impeller is correct for my engine, and the pump model too. Kinda like advice to turn the computer off and then on, but these pumps are dead simple and incompatibility needs to be ruled out.

 

[G Kiba]

Impeller vanes will flip to the direction that it spins. You can install them either way i am told. That is if they are spinning. I had a new impeller that separated at the hub after a few hours. If the pump was removed, check that the shaft was correctly assembled into the slot that drives it.

 

[Bolo]

There is one line in your description of the problem you‘re having that I find very curious and keep thinking about. You said, “The Sea Screen fills with a darker water as if the water is going in the wrong direction.” Please don’t take offense at my suggestion but are you sure that the hoses are connected to the pump properly. By that I mean is the pump INPUT connected to the strainer and not the engine. I’m thinking that if the hoses are reversed maybe the pump is pulling what ever water is in the engine and back filling into the strainer.

 

[Christian Williams]

Swapped out all hoses from Thru-hull up to water pump.

Hmmm, very interesting. Not that I've ever put things back together wrong, of course.