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Question Checking Lower Unit How to pressure test

E

enginesilo

Contributing Member
"What is the procedure to test

"What is the procedure to test a lower unit? After checking the current oil to see if it has any water mixed in, is whitish or creamy, the next step would be to pressure test the Lower End.

Can a typical gauge pump or carburetor pop off tester sufficiently test the pressure of a lower unit?

What is the procedure and what is the pump or tool needed. Could the pump be built?

How long does the unit need to hold pressure for, and at what psi?"
 
"Hi...If you arte getting wate

"Hi...If you arte getting water in the lower unit, then it needs to be re-sealed..If not, then the lower unit seals are still OK....The pressure-vacuum test is 3# both ways..I think thats correct, and should hold for about a moment or so..."
 
"Hi Tom,
This is a boat that

"Hi Tom,
This is a boat that I am on the verge of buying. The boat was winterized so my guess is that it already has new gear oil inside. I am planning on pulling the lower plug to see if it has any water in it, but again since it was winterized it may not show.

So I was planning a simple pressure test to see if it will hold pressure as an indicator that the seals are good. I may get a fitting and a bike pump with a gauge.

How much pressure should it hold? Someone else recommended 10psi, is that too much or good? and should it hold for a specific time or indefinitely until I let it out?"
 
How about a test for one that

How about a test for one that is not a re-seal job? I am testing out a unit that has been maintained by a marina all of its life and want to check it on my own prior to buying. Will 5 minutes be sufficient? Will it lose any pressure as time passes or it should hold the number rock solid?
 
"u r making this too complicat

"u r making this too complicated,...like tom said,..if engine has wtr or milky oil...needs to be re-sealed....if not,..chg oil and go...most will lose pressure on old seals after a while..old seals,worn shafts will eventually leak a lil....after a re-seal job,..we are just double checking our work...and the integrity of the gearcase seal area's...shafts etc."
 
"The engine is a 115hp.

My

"The engine is a 115hp.

My first plan is to see if there is any water or milky oil, along with excessive metal chips on the drain plug. If that all checks out I may do a simple pressure test, and then refill."
 
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