Evinrude E-NATION, for those dedicated to water, power, fishing and fun
Posts: 1
Registered: ‎06-07-2019

1980's E70 lower unit oil leak

[ Edited ]

On the lower unit there are two gear oil drain plugs. After being out on the lake motoring around last weekend I tilted the motor up after arriving home and discovered that oil leaking out of a small port next to the upper drain plug. Does anyone know the probable cause for this? 

Posts: 9,445
Registered: ‎07-14-2011

Re: 1980's E70 lower unit oil leak

Chances are that little port is a drainhole for a cavity in the gearcase to keep any water trapped that could freeze and cause damage.

If the oil is from the gearcase, then you may have leaking seals or o-ring. If it looks like exhaust and oily residue, it could be dripping down the exhaust areas due to incomplete combustion or a very rich mixture.




"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 



The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.