In the 1950's, 60's and early 70's, Mercury Marine had steel drive shafts that would corrode away directly under the water pump where the upper gear case seal contacted the drive shaft. Because they used lower unit grease they called 'special lower unit gear lube', it was not as problematic as it would have been if they used 80 to 90 wt lower unit lube like some other manufacturers.  Mercury started using double seals and stainless shafts which made their gear cases as good or better then their competitors.  They dropped the 'special lower unit gear lube' with the improvements to the lower unit seal problem.

I started working on outboards in 1972 as a full time occupation and throughout the years, I found that Johnson and Evinrudes had a similar problem with their lower unit, but for a different reason - their lube level was too far below the upper drive shaft bushing/bearing.  Over the years while working on numerous lower units, I found many small and mid-size outboards of all makes, with water in the lower unit gear lube (sometimes there was only water with no gear lube). 

I started using the Lubriplate Gear Grease in the early 1980s. I used it as a First Aid Kit to help customers to get through a vacation or expected company situation.  Once this product gets on the lower unit internal parts, the water is prevented from getting in contact with the gears. I meant this to be a short time "bandaid", but some of the customers have never repaired or replaced their gear case, they just check the gear grease level frequently and keep it full of grease. Some motor values are less than proper lower unit repairs would cost. This First Aid Kit allows you to squeeze more time from your old motor lower unit.  The First Aid Kit will have the tubes of grease that you order; as well as FREE drain plug seals and FREE instructions for draining and filling the lower unit.  Please e-mail us with the make, year, and HP of  your motor so that we send you the correct free drain plug seals for your lower unit.  See "Contact Us" page to enter and e-mail the information when you order the grease.

A word of caution!  I have never used this method on motors over 100 HP.  Also, do not try this method in electric shift or hydrolic assist OMC lower units.