Re: Mercury Mark 5 Lower Unit

[hotrod]

I looked at the Mark 5 and Mark 6 parts lists. There is no bearing in the water intake housing, only an oil seal. The seal is not illustrated in the illustration, just listed with its part number. The lower driveshaft and prop shafts each have 2 bearings for each shaft (one needle bearing and one ball bearing per shaft). The needle bearing is pressed into the gearcase housing for each of the 2 shafts. These bearings each have their own part number and they are not illustrated (they cost $1 each back then). Pressing them into the gearcase is the first step in gearcase assembly per the instructions. Each of the 2 shafts also has a ball bearing on them. Each bearing has its own part number. I don’t know if Mark 6 parts can be installed in a Mark 5 case. You may have to do some measuring and possibly shim as needed for gear mesh & clearance. There may be a Mercury website for more info.