3YM30 raw water pump seal orientation

[Halo]

I am refurbishing my raw water pump. The parts manual seems to show that the solid face of the seal faces towards the impeller with the spring and open end of the shaft seal towards the bearings.
On a video of how to rebuild the pump it shows the open end of the seal towards the impeller.
Which orientation is correct please?

 

[VicS]

The open side with the spring should face the impeller!

 

[Halo]

Thanks Vic. I was coming to that conclusion and it is a general rule that the spring is on the fluid side but it seemed odd that the parts manual has it wrong and I wondered if it was to protect the spring from sea water. Hopefully is a stainless spring

 

[vyv_cox]

Thanks Vic. I was coming to that conclusion and it is a general rule that the spring is on the fluid side but it seemed odd that the parts manual has it wrong and I wondered if it was to protect the spring from sea water. Hopefully is a stainless spring

The original spring in the 3GM30F pump was a copper alloy, maybe beryllium based(?). It lasted quite a few years but when rebuilding it I found that the exact replacement for a Volvo engine had a stainless spring. I fitted one of them.

 

[BobnLesley]

The original spring in the 3GM30F pump was a copper alloy, maybe beryllium based(?). It lasted quite a few years but when rebuilding it I found that the exact replacement for a Volvo engine had a stainless spring. I fitted one of them.

Alternatively, buy one from your local Bearing Factor and you'll get a s/steel sprung one for a fraction of the cost of either a Volvo or Yanmar one.
The attached photo details the order and orientation of a 3GM pump, I believe the YM used the same unit.

 

[vyv_cox]

Alternatively, buy one from your local Bearing Factor and you'll get a s/steel sprung one for a fraction of the cost of either a Volvo or Yanmar one.

Always possible at home but I bought mine at Ionian Boat Assistance at Nidri.

 

[vyv_cox]

Interestingly, I checked my records. My Yanmar engine, with a copper alloy seawater pump seal spring, was installed in 2000. The seal failed in the Ionian in 2009, when it was replaced with one with a stainless steel spring. That failed in 2014 on Ios. I had a stainless spring replacement with me, which failed in 2018.

As far as I remember none of the springs had actually broken or corroded through. It seems the copper alloy one was at least as effective as the stainless ones and possibly more so.