'85 50hp evinrude gearcase

[itmustaben]

i have a 1985 50hp evinrude that has water in my lower unit. not much but some. so i ordered a gear case seal kit which comes with various o-rings and gaskets. but i am not sure where some of them go. the package has not yet arrived but i am sure that when it does it will not have directions or a diagram so could someone lead the way for me. some of them are obvious but others are gonna be a mystery to me. will i need to remove the prop. or the drive shaft? how long will this take for a dummy like me, a couple of hrs? will i need to use extreme care anywhere during this process?

 

[Vic.S]

Re: '85 50hp evinrude gearcase

I very strongly recommend an OEM workshop manual or you will probably have difficulties.

If you insist on doing it without a manual (as I probably would!) you will find the exploded diagrams on the BRP parts website useful. See here

Note in particular that the seals on the prop shaft and on the drive shaft go back to back as shown on the diagram.

You will need to remove the prop and the drive shaft.

You will also replace the water pump impeller wont you! You'll need the water pimp kit as well. Watch out for the key!

I guess you will also repace the anodes so you will need an anode kit

For a complete dummy allow a lot more than a couple of hours.

 

[kjdunne]

Re: '85 50hp evinrude gearcase

In order to reseal the gearcase completely, you need to remove the gearcase from the engine. You need to remove the prop, the bearing carrier between the prop and gearcase, and the shift rod. The water pump assembly is also removed. You do not remove the driveshaft. The bearing carrier requires a puller (harmonic balancer puller) and 1/4" x 20 TPI all thread rod (2) of appropriate length. I use 12" rods on my '89 40hp which are plenty long. As you remove the various seals and O-rings, match them with the new ones in the kit, and it becomes obvious which ones go where.

The prop shaft seals at the aft end of the bearing carrier are the trickiest to remove for the novice without the special tool. I use a hardwood dowel from the gearcase side to drive them out. Don't use a screwdriver as you'll probably gouge the bore they fit in. Trust me.

The shift rod height after reassembly is critical for proper operation. You should check with a dealer or shop to find out if they will set it for a reasonable price.

Get an OEM service manual to guide you. The aftermarket ones are too general.

 

[Reggie08]

Re: '85 50hp evinrude gearcase

I recommend before tearing into it, replacing the washers/seals on the fill and drain screws, replacing the lower unit oil then re-checking the oil after running it for a little while. Most leakage comes from the drain/fill screws and bad washers/seals.

 

[kjdunne]

Re: '85 50hp evinrude gearcase

Good point, Reggie.