Manuals or instructions on this gearcase

[Too wright]

I've just purchased this gearcase and ran it and it is getting water into the oil , does anyone have a manual or a parts diagram so I can give it a rebuild , im in Australia also ,secondly in the interim what gear oil can I use which doesn't thicken with water and agitation from the gears ,the oil I'm using at present is ANGLOMOIL 100% synthetic , grade is sae90 thanks for your help Graham

[KURPS]

If the case is not cracked, then the seals are leaking. The prop shaft is removed by taking the cone off. The cone is threaded into the case with a left handed thread. You will need to make a special wrench to remove the cone. The wrench should be made like this: to a steel ring a little bigger than the outside of the cone - weld 4 square bars to the inside of the ring to match the grooves on the cone - weld a steel handle to the ring about 24" long.

Clamp lower unit in a vise, place wrench over cone and turn clockwise to loosen.

Nock out prop shaft seals and replace.

Don't run lower unit with oil/water!

Gear is located on driveshaft with a square section and held in place with a nut

[Too wright]

Thanks for the help

[dwhitford]

I ran 2 0f these in the 1970s and '80s under my Quincy Z250. The units are robust, but maybe slightly slower than the later split-case gearcases .. . . not entirely sure of that because I never had the opportunity to make a back-to-back test. But if Yamato replaced these gearcases wholesale with the later split-case units, they must've thought the later units were better somehow

Do what Kurps recommends above. I always ran OMC hypoid.80-90 oil in my units and never had a failure. I'd drain and replace the oil after every race. Some even better high-pressure lubes are now available.

[Too wright]

Thanks for the info , any chance of a were I may find a spare parts manual ,and I'll replace the seals this week .👍