Re: 1952 7.5 evinrude?
Sorry, Mr. Ross.
Soliciting private transactions is forbidden in the forum.
I am not certain about the '52 7.5, but most JohnnyRudes have two plugs with slotted screw heads just above and just below the starboard (right) side propshaft bulge on the lower end. The top one is called the VENT and the lower one is the DRAIN/FILL.
Remove both plugs (CAUTION!! Do not remove the phillips head screw. It positions the shifting clevis.) and the oil will drain out the DRAIN/FILL hole.
Pump the new gearcase oil in the DRAIN/FILL hole until oil overflows out the VENT. Replace the VENT plug including a fresh gasket.
With the VENT plug installed the oil will not drain out the DRAIN/FILL hole because of airlock.
Reinstall the DRAIN/FILL plug, also with a new gasket.
If you don't have the two plug system, tell us what you have and we can get you through that.