Pressure test lower unit

[jon75127]

Is there an easy way in a home shop to pressure test a lower unit? Can I pressurize with compressed air?? Lube in or drained? Replace with a different fluid?? Any ideas??

 

[SpinnerBait_Nut]

Re: Pressure test lower unit

jon, welcome to iboats.
Let's get this to the right forum for your answers.

 

[Chris1956]

Re: Pressure test lower unit

Jon, You can pressure test a LU. Drain the lube, remove the LU, put a bicycle pump on the vent or drain screw (rig up some kind of adaptor) and pump it up to a few PSI. Spray some soapy water on the waterpump base, shift rod prop shaft, vent screw and if no luck, remove the impeller and spray some on the driveshaft.

 

[jon75127]

Re: Pressure test lower unit

Thanks Chris1956-

I will give it a try. I'm still working on an adapter.

Thanx again.

 

[Smig]

Re: Pressure test lower unit

.... I'm still working on an adapter.

Take the valve stem from an old bike tube and clamp on the fill hose from a lower unit oil pump. Since you have a valve on it - it will stay pressurized while you chase down the leak. Since you won't be pumping and making noise the whole time, you may even be able to hear the leak...

 

[Marc III]

Re: Pressure test lower unit

Don't exceed 16 psi. I use a small compressor and check presssure frequently. Submerge the gearcase in water to find leaks. Replace the drain/fill screw o-rings.