1989 30 hp water pump

[JRM80000]

I am resealing the water pump in my 30 hp Yamaha and after removing the two seals in the pump housing, I see a hole in the casting that passes between the lower portion of the pump housing to the upper portion of the seal area. It appears the hole is intended to be there, but I can't figure out what it does. It seems to me that the hole allows water to enter the area above the upper drive shaft seals, but the question is, why. I wouldn't think cooling is necessary although maybe it is. Can anyone explain the purpose of this hole so I can understand what I am doing? Many thanks.

[Jason2tpa]

I am resealing the water pump in my 30 hp Yamaha and after removing the two seals in the pump housing, I see a hole in the casting that passes between the lower portion of the pump housing to the upper portion of the seal area. It appears the hole is intended to be there, but I can't figure out what it does. It seems to me that the hole allows water to enter the area above the upper drive shaft seals, but the question is, why. I wouldn't think cooling is necessary although maybe it is. Can anyone explain the purpose of this hole so I can understand what I am doing? Many thanks.

Apologies cause I'm not following you whatsoever. There are no oil seals above the cartridge plate, which is where the impeller "housing" is located. There is no "housing" below the cartridge plate, which is where the oil seals are located. And there are certainly not 2 seals "in the pump housing".

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