This early style pump assembly A90460 (marked G9320 on front cover) is used on all 850X, 850Y, 652X, 652Y.
It was superseded by late style A90621 (marked SK2096) for 851, 852, 653, and 654.
As units they are interchangeable, but the internal parts are not.
Water pumps were painted green at the same time as the engine. It is secured to the block with three different sized studs:
- Two A5-67
- Two A90412
- Two A90413
Gasket A90395 seals the pump to the block.
There are four NF6 nuts and two NF5 nuts with appropriate lock washers on the studs.
The water pump cover is secured to the body with gasket A90393 between and four SA506 hex head cap screws plain or marked W, and WB5 lock washers.