I bought a used boat with a 2000 150 johnson and as I went though I found the prop seal on the lower unit damaged and the oil was badly contaminated and very very slugish. So I replaced the seal, put new oil and i took it out a couple of times. Checked the oil again and the oil is white again. Is this contamintaion from the old oil? The old oil was very thick and some of might have stayed in the unit. The seals look good. I have never owned a boat before so this is new to me. Should I change the oil again? Do I have another leak?
Thanks

First problem, their are 2 seals stacked on the prop shaft. I allways flush out lower with B-12 or simular product. You could have carrier seal leaking? Have found it best to remove carrier when replacing prop seals. Their is an "O"ring at back end of carrier, clean everything up real good with B-12 and reseal "O"ring with black RTV. Permatex sealant on prop seals, emory the prop shaft so the new seals will seat. Should not see white in gearcase if you flush it good. Good Luck

I have a mighty vac but I can't seem to make a seal to test the lower unit. Is there something i should be using or do I just rig it somehow. Thanks for the advice. Thanks

b-12 carb cleaner, gary?

jor, my manual says pressure test using a hand vacuum pump w/gauge screwed into the drain/fill hole - if it fails pressure test, submerge & look for bubbles.

hope that helps.