Re: Johnson 1993 48- where are shims, leaks
Oil and water in new gearcase oil appears as a creamy light color, not usually gray but always creamy.
If you drain the oil, it will be easy to spot because water is heavier than oil and the mix will be first out of the drain hole. Be sure to replace the seals on the fill and vent screws with new ones, that is where the most leaks occur.
The easiest way to find gearcase leaks is to do a pressure test. You will need to remove the gearcase and the water pump first, so that you can observe the area of the seals on the driveshaft and shift rod.
10 to 12 psi and some dishwasher soap is adequate to spot most leaks. if you don't see them, immerse the unit and look for bubbles.