1975 - 70hp Johnson lower unit pressure build up

[Keith Carlson]

What would cause pressure to bild up in the lower unit. The lower unit had two small holes towards the top that had been welded at one time. We ran the motor with new grease. Went to take out the drain plug and it came off like a bullet out a barrel of a gun there was so much pressure. The new grease was burnt black.

 

[Dave Abrahamson]

Re: 1975 - 70hp Johnson lower unit pressure build up

Me thinks this might do better in the Johnson repair forums.<br />Just an FYI.<br /><br />Dave

 

[Mod3]

Re: 1975 - 70hp Johnson lower unit pressure build up

Moving to Johnson & Evinrude Troubles and Repair.

 

[rodbolt]

Re: 1975 - 70hp Johnson lower unit pressure build up

its rather normal. when filled and allowed to heat in the sun it will pressurize the air above the driveshaft bearing. at least ya know your seals are ok.