Homemade Gizmo To Pressure Test Lower Unit

[Thornback]

Here's a photo of the gizmo I made up to put air pressure in my lower unit to test the seals and O ring. The gizmo was made up of a lower unit lube oil pump and a tubeless tire valve stem with the connections glued together with JB Weld. The yellow hose connects to the tank on my air compressor. The pistol grip, trigger, and gauge connects to the yellow hose. The pistol grip hose snaps on to the tubeless tire valve stem of my gizmo. One end of the gizmo screws into the oil drain hole in the lower unit.

[Smallie_Stalker]

Very cool Thornback!!! 

[Bigwrench]

How do you regulate the amount of pressure or how much should you use to test it ?
I could make one of these and sounds like a great idea but worry about blowing out the seals or orings with too much air pressure ? Do you have a way around that ?

[Thornback]

How do you regulate the amount of pressure or how much should you use to test it ?
I could make one of these and sounds like a great idea but worry about blowing out the seals or orings with too much air pressure ? Do you have a way around that ?

As you can see there is a trigger and you press it very lightly and quickly release. The trick is to bleed in a small amount of air as possible. You could practice pressing the trigger before connecting the air hose to the unit. You can also see there is a gauge to tell you how much pressure you have in the lower unit. I'm sure if you put too much pressure in the unit it would blow out the seals. Heck you can blow out a tire if you put too much pressure in it. The mechanic at the boat place told me they use 10# of air pressure to test for leaks. Mine held at 19# so take your clue from that.

[Bigwrench]

I guess I was just wondering how you achieved it. That makes sense now. I run about 150-180 psi on my compressors so would definitely have to use a regulator to bring it down , not easy to "bleed a little bit at a time" at that industrial pressure is why I was curious and a shut off valve to seal it off would also work perfect  but that's a great tip and thanks for the added info ! 10 psi was what I was looking for !
And your definitely right about blowing a tire have see guys retired early over that mistake more than once