Re: Need Part Number for Water Pump Impeller Housing 1977 70 hp
It seems there were two lower unit gear housings that could have been used on the 70 hp engines from 1974 - 1978, a small and large case type. Easy way to identify them is the number of holes on the water intake as below.
SMALL CASE: Evinrude / Johnson outboard parts for 2 & 3 cylinder loop charged small gearcase identification for old style lower unit years 1975 thru 1988.
Physical characteristics 15 1/2 inches tall with straight at the trailing end of the gear housing and the fin pointed at the trailing end of the cavitation plate.
Six holes above the cavitation plate with internal water intake screens (four holes) and no speedo pitot hole.
2 cylinder 40 to 60 horsepower and 3 cylinder 60 to 75 horsepower loopcharged small gearcase years 1975 thru 1988 used Impeller Housing 384087.
LARGE CASE: 2 & 3 cylinder loop charged large gearcase identification for lower unit years 1975 thru 2006.
Physical characteristics 17 and 7/16 inches tall with straight at the trailing end of the gear housing and the fin.
Pointed at the trailing end of the cavitation plate
Six holes above the cavitation plate
Internal water intake screens (three holes) and no speedo pitot
.
The large gearcase 2 cylinder 40-60 hp years 1975 thru 2006 and 3 cylinder 60-65-70-75 hp years 1975 thru 2001 used Impeller Housing 438543.
This link has a very definitive explanation of OMC lower unit types and their identification.
http://www.sterndrive.info/outboardmotor/help_identifying_lower_units.html
The GLM Marine Parts catalog has listings for all.
http://www.glmmarine.com
Steve
