I seem to have a small leak of oil from the shaft by the prop when the motor is stored horizontally. What kind of oil should be in there? How hard is it to replace the seal, and are they available?
90 weight gear oil(wichever brand you prefer).. very easy to replace and yes they are availible. dont store your motor horizontally, its motor abuse!!
remove your prop(nut and cotter pin)
you have 6 bolts that hold your skeg/fin to the lower unit, and 1 phillips head bolt. remove the phillips and 6 bolts. grab the prop shaft and hold it up before you pull the skeg off so the assembley does not fall out, after the skegs gone youll see the shaft,gears,bearings etc..there will be a yoke that holds a cradle on the dog( little gear between the big gears) let the yoke and cradle drop down or pull it down awayt from the dog, now you can remove the shaft with everything still on it to replace the seal on your hub(big round bearing closest to your hand when you grabbed the shaft before removing skeg) the seal is a o-ring type.
also inspect the gears to see if they are rounded or really worn....
that phillips head bolt goes through the yoke below the cradle to give it a pivot point to engage the dog into fwd or rev.
getting everything back together is a bit tricky, u may wanna have a xtra hand to help.
when its all back together, spin your prop while shifting from neutral to forward, back to neutral and then reverse to make sure its right.. pm me if you want to see a good diagram