1973 Merc 7.5 - lubrication questions

[metriccrescentwrench]

I'm nearly finished refurbishing this engine , and have just a couple more questions (I hope).

1) Does this engine run 24:1 or 50:1 gas/oil ratio?

2) How much gear lube does the lower unit take? Seeing as how high the gearcase vent screw is, it just doesn't seem right to fill it all the way to the vent hole (but I've been wrong plenty of times before).

OK, 3 questions... Does this use standard Hi-Vis gear lube?



thanks

 

[Texasmark]

Re: 1973 Merc 7.5 - lubrication questions

I had a '74 of that hp. 50:1.

Lube for that will be about a pint. Any Merc or Pennzoil marine lower unit grease/oil/fluid will work as that is not a high performance application but you want the stickiness that the marine formulas provide over normal hypoid oil. Fill procedure is to introduce from the lower hole till it runs out the top hole, install the top screw then quickly remove the lube source and install the lower (drain) screw.

Mark