Hey all 1978 Merc 90 6cyl. 4846419 I have gear oil slowly seeping out 2 holes on my lower unit ... can someone shed some light on to how/why thank you all
Looks like exhaust residue draining from the weep holes, they drain water from the mid section.
The exhaust passes through the mid section, and leaves residue behind.
Its gear oil allright, , I noticed it last week so I changed the gear oil and its still the same someone mentioned a shifter seal might be gone what do you think? Thanks guys
I think that if it is in fact gear oil the oil in your lower unit will be discolored as a leak leaks both ways. When you put a hot lower unit into cold water, like when you launch your boat, the oil in the lower unit shrinks upon cooling down, creating a suction which can suck in ambient water through the leaking seal....if you have one.
Places for leaks are that seal, the seal on the drive shaft under the water pump assy, the prop shaft seal, and the seals under the drain and vent screws. A pressure test of the LU will tell the tale. I think my manual says 5 psig for 5 min. no drop in pressure.
Smell the stuff. If it stinks, it is gear oil. If it smells like gasoline or oil, it is residual fuel. If it is gear oil, change the waterpump base driveshaft seal.
