Mercury 2.5 200 hp Lower unit

[RiChavis]

Think this motor is around 1990 Mercury carb . 2.5 200 hp with a standard 1.87 ratio lower unit .
What is the correct procedure to pressure test this foot . How many pounds @ diff. setting and how long should it hold pressure @ each reading .
I think you check 3 place's .....prop shaft / drive shaft / and gear shaft seal ?

Thx for any help .

[RiChavis]

TTT No one know the spec's of air pressure that you need to use to pressure the lower unit .
From a another forum , a member said he does 10 psi on his sport master , but did know on a standard lower unit .?

[Capt.Insane-o]

10-12 pounds. Too much and it will blow past the shift shaft seal first.

[FUJIMO]

You can also do 6 pounds. As long as there is no leakdown. Thats what you need to see.

[RiChavis]

Thx 6 - 10 pound's is in order .

[Go Time]

It is more important to test under vacuum. The normal failure mode is with water being sucked in when the case cools after being run and vacuum testing checks those seals. I use a brake vacuum fill pump and pull 15" for 15 minutes. A good case will drop less than 1", Most dont drop at all.

[RiChavis]

Thx Go Time
Had one on order to do the brake's on the trailer . Just came in the mail before i headed out to work .