Seal Replacement

[darrellbud]

is it hard to replace the seal in the lower unit on a spl 48 hp evinrude, my lower unit fluid looks milky and i assume its water getting in. thanks

 

[HighTrim]

Re: Seal Replacement

That depends on which seal. Did you change the vent and drain screw when you changed your lu oil? That is the first spot I would look to. After that, you will need to do a pressure test to locate the faulty seal, or simply replace them all. Do you have a manual?

 

[darrellbud]

Re: Seal Replacement

all i have ever done is drain the lower unit and add fluid. i bought the engine used without a manual.i don't know about a screen

 

[HighTrim]

Re: Seal Replacement

Those gaskets on the drain and vent screw are the number 1 spot for water intrusion, and need to be changed each and every time the lower unit is serviced. They are cheap, so grab a bag of them next time you are at your dealer.

I would try replacing them first, along with a quality full synthetic lower unit oil. Take if for a run, then check out the oil. The water will sit beneath the oil, since it is heavier, so it should come out first when the drain screw is loosened. If it is still milky, the water intrusion is elsewhere. You can pressure test it, or replace all seals. What is your model number? I would also reccomend getting yourself a service manual, it will pay for itself a million times over, especially if you are going to be digging into the lower unit.

 

[HighTrim]

Re: Seal Replacement

To pressure/vacuum test a lower unit:

a) drain the gear oil
b) use an appropriate adapter with a gauge tee'd in to apply pressure or vacuum. No more than 15 psig for pressure. You can use a bicycle pump or any other compressed air source for pressure. For vacuum, you need a vacuum pump.
c) LU should retain some pressure or vacuum for 45 minutes minimum.
d) If pressure doesn't hold, submerge LU in water to find leak source [possibilities: drive shaft seal, prop shaft seal(s) (usually two), shift shaft seal and the fill/drain screw washers.]
e) replace offending seal(s) as required.

 

[darrellbud]

Re: Seal Replacement

hey thanks for the info i never about the vent screw gasket, i was'nt sure what it was untill i looked at the diagram. thanks darrell