Evinrude Lower Unit Pressure Test Question

[outsick81]

I have a 1998 Evinrude FICHT lower unit from a 175 hp. I bought the unit and it was drained of oil, but what was left looked ok. When I pressure tested it, I could hear it seaping if I put my ear to the vent holes that are in the middle area of the lower unit. Also, I noticed that when I accidently bumped into the shift shaft more air would seap out. So if I rock the shift shaft air leaks fairly easily. Anyway, I went ahead and tested with the 7 pounds of pressure that it would still hold. After 3 tests at 45 minutes each, the unit still holds about 2 lbs of pressure. Any thoughts on if this is seriously abnormal; and what could cause this. Should I have all of the seals replaced? Any thoughts would be very helpful. Thank you in advance!

 

[ezeke]

Re: Evinrude Lower Unit Pressure Test Question

That's fairly typical of the gearcases. The seals on the shift rod are redundant o-rings and they hold fairly well, but wear due to the shifting over time. They are not very hard to replace if you have the time.

 

[outsick81]

Re: Evinrude Lower Unit Pressure Test Question

Ok thank you very much for the info. I am actually selling this lower. I just dont want to screw someone over on it if the seals are bad. Btw, I did a vacuum test and it held great with no leaks.

Being that it does still hold a couple lbs after 45 minutes, and holds vacuum do you have any theories on if it would likely seap water in while under normal operation?
Thanks!

 

[outsick81]

Re: Evinrude Lower Unit Pressure Test Question

I removed the cover for the shift shaft and you are right the o rings are simple to replace. I will change this week and give update.

 

[ezeke]

Re: Evinrude Lower Unit Pressure Test Question

If the shift rod leaks air it will probably leak some when in use because the unit heats up and then cools off.

Changing those o-rings is not much trouble with the gearcase off the motor - maybe 15 minutes but no more, and 2 o-rings and one gasket for the cover.

 

[wilde1j]

Re: Evinrude Lower Unit Pressure Test Question

If it holds some pressure after 45 min., it's fine.