Am running a 1955 Mark 25E 18 hp Merc,Original specs. call for Lubriplate in lower unit,I am presently using Mercury Premium Gear Lube in it. What are the opinions here as far as using either lube,I Don,t want to damage the unit by running the wrong lube in it as i now see that its possible to purchase Lubriplate ,that i did,nt know before i started using the merc. gear lube. I got two different answers from two local repair shops here? Thx in advance from an ole Merc Man.