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HELP....Merc Propshaft seals

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Noticed a bit of oil under the outboard (1993 135), pressure checked lower unit and definately need to replace the propshaft seals.

Anybody have a quick how to? I have the seals just not sure how to get the little buggers out of there.

Thanks in advance.

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You have to remove the bearing carrier first. Once you pull out the carrier, then you can use a seal remover to remove the seals. Reinstall new seals back to back.

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How do you pressure check the lower unit? I have a 1988 9.9 Evinrude that I just noticed is leaking milky colored lower unit grease. I'm assuming it's the prop seal and was going to take a stab at fixing it this weekend. Can I do this myself? If so any tips would be appreciated.

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You need to have a pump with a reliable low pressure gauge. You can buy one specifically for this.(I made mine)

You need to drain the oil completely.

Reinstall 1 plug with washer or gasket

Screw fitting of pressure gauge into the other hole.

Slowly pump it up to 12 lbs psi. Over 10 for orings, but under 15

for the seals as you do not want to over pressure and "puff out"

the lips of the seals.

Observe the gauge for loss of pressure.

To pin point the leak, use a soapy solution around prop shaft, drive shaft, shift shaft, and plugs. You will need to remove the lower unit from the rest of the engine to check the drive shaft and shift shaft.

Vacuum testing is a little different

Hook up vacuum guage the same way, but make sure gauge is in top hole- if it is in the lower hole it may suck in residual oil.

To find the leak, squirt a little light weight oil around the same parts. the leak will briefly stop as the oil is pulled into the leaking seal or o ring.

Hope this helps.

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