1977 Evinrude 4HP Outboards Service Manual, PN 5303, Page 56Get this manual
WATER PUMP SERVICE STANDARD GEARCASE WATER PUMP aRemove two water pump screwsSee Figure 6-4While holding driveshaft down in gearcase, slide impeller housing cover and impeller housing cup off of driveshaftSee Figure 6-5
IMPELLER KEY WAY
IMPELLER
IMPELLER HOUSING COVER
I MPELLER INST ALLATION
GROMMET WATER PUMP ASSEMBLY
Figure 6-6Impeller in Impeller Housing Cup
WATER GROMMET IMPELLER HOUS ING COVERI MPELLER PLATE IMPELLER
I MPELLER DRIVE KEY
Figure 6-4Water Pump Assembly (Standard Gearcase)
IM PELLER HOUSING SPACER WASHER