2018 300 Sportmaster lower gear lube

[jayfaro]

2018 300xs Sportmaster
#1E053915
Hey guys
I pulled my prop to check out the gear lube and it’s milky. With the winter coming I drained the gear lube and bought the Merc Hi Perf gear lube and the pump. It took all 32oz and didn’t come out the top vent hole. I did an internet search on the gear lube capacity on the SM and I found a bunch of different answers so thought I’d go directly to the man Don!

I can’t remember how long ago but do remember seeing something from Don about this but can’t find it. I thought it had to do with adding 32oz and then draining a couple ounces out once it started to come out the top.

Anyway, I’ll be bringing it for seals in the spring and won’t be used again this year.

Thanks Don and the gang

Jay

Also do you sell the upper vent screw and lower fill screw along with the seals or just the seals?

[Bryanmc57]

Fill it until it comes out the vent hole. They all vary in how much they will hold so don't get hung up on a number, then drain a couple ounces out (although I don't think that will matter since you're not going to run it before they drain it to reseal it).

[DewRonInc]

I have had better luck with the actual mercury racing gear lube, seems it doesn't gain as much with heat, something was differant. Mercury racing tech said I would have less issues using that product in the sportmaster.....

[EuropeanAM]

High Perf is acceptable, but the Racing Lube is what's recommended. Actual capacity varies from one case to another (have seen anything from 24 - 35 ounces).

We do carry replacement vent and drain screws, as well as seals (virtually any Mercury Part can be ordered through our Parts Department- see Rhonda's post, pinned at the top of the Forum for contact info).

[jayfaro]

Don,
I know the Racing vs Premium Plus oils cant be mixed and was afraid to use the Racing Gear Lube since there would still be some residual in the lower unit. If a small amount of residual of the Hi Perf gear lube is acceptable i'll just use Racing in the spring. Let me know if this is ok to do. Thanks for everyone's input!

Jay

[EuropeanAM]

Allow the gearcase to drain overnight, after which you are fine to switch. If you want to go the "extra mile", flush a few ounces of the racing lube backwards (into the vent screw) and then let it drain overnight.

[DewRonInc]

Yup