3GM30F raw water pump missing impeller vanes

[Jimongee]

Hello again and here I am on a totally new problem on my recently purchased C & CMKIII
Mind you after 600 miles on the water in the last 14 days as I brought this home from Canada back to the US with lot of motoring… Today we haul road and I decided to winterize can I couldn’t get any coolant through the heat exchanger. So after a short diagnosis, I decided something was going on with the raw water pump and lo and behold. There are at least two vanes missing on the impeller! so here’s my question of course I’ll put a new impeller in, but what about those missing vanes -Is it something I have to worry about or will the system just pass those through the heat exchanger?
I’m sure this is not a unique problem to us sailboat owners. The sellers had told me they always did all the maintenance on everything but now we know that is not accurate. Thanks for any help you can give me. I really appreciate it.

 

[kappykaplan]

but what about those missing vanes -Is it something I have to worry about or will the system just pass those through the heat exchanger?

Best to open the heat exchanger and look for the missing vanes/pieces of vanes.

 

[Tally Ho]

They had to go somewhere…

Most typically in the hose from the pump to the HX or at the HX tubes.

And they will block water flow…so best to find and remove them.

Greg

 

[Ralph Johnstone]

I'm afraid all of the above bad news is quite true. But fear not, going into the heat exchanger is not all that bad. I did it a few years ago during the winter.

Here are a few shots of what you'll find inside. Mine is the 2GM but the layout is similar and the 3GM may include a few extra tubes thrown in for good luck. Scratch mark everything so all parts will go back in exactly as they came out.

You will need the the one gasket which for the flow return and the 2 large "O" rings. The most important parts of the whole job is to clean all gasketed surfaces to shiny metal and lubricate the 2 "O" rings with a NON-petroleum grease such as SuperLube. This will ensure they will slide exactly into the correct position. If they are not perfectly seated, this will allow flow between the sea water and the coolant which causes a loss of sleep at night.

 

[kloudie1]

The big o-ring cover seal is Yanmar # 24311-000700.. The gasket that seals the tube sheet to the cover is Yanmar #128695-44070. Ya need two each.. You may be able to re-use the old ones but good to have them on hand..
Congrats on a good sailing boat!

 

[Jimongee]

Thankyou Ralph and Kloudie…I will do this….

 

[jssailem]

Nice info @Ralph Johnstone. His HE looks clean. Mine was crusty with evidence of corrosion.

The bits of vane’s missing from your impeller may be found lodged in the HE tubes, or may be stuck in one of the hoses from the pump to the HE. Check the full path or you may find yourself repeating this task.

I found a small wooden dowel made a decent tool to clear each of the tubes.

While you in this task would be a good time to replace the pencil zinc in the HE.

 

[BigEasy]

I used a gun cleaning bore cleaning tool with a 22 caliber brass brush attachment. Fit perfectly and allowed me to clean out barnacles & built up crud easily & effectively on a 2GM20F Yanmar. Solved my overheating problem on a previous boat.

 

[BigEasy]

I did it a few years ago during the winter.
Here are a few shots of what you'll find .

Nice write up & photos Ralph!

 

[Jimongee]

Thanks to all who responded. Update: just put the tools away. Got lucky. Removed the inlet hose on the HE and found both pieces from the fragmented impeller. Did not have to remove the HE cartridge. Reassembled with a new impeller and now have great flow. Since this has always been a fresh water vessel I was not concerned about build up barnacles on the HE cartridge. What do ya’ll think?

 

[kloudie1]

If no overheat problems, no need to play further..
Good job!

 

[kappykaplan]

Since this has always been a fresh water vessel I was not concerned about build up barnacles on the HE cartridge. What do ya’ll think?

I think you're in great shape!

 

[Ralph Johnstone]

Removed the inlet hose on the HE and found both pieces from the fragmented impeller.

I think "Ripley's Believe it or Else" would give you an award for that bit of information. Seems hard to believe but there you have it .........................

 

[jssailem]

Well done!