Pressure testing lower unit

[innovator]

I had water get into my lower unit this summer, I believe it was from a loose vent plug. I was reading in my shop manual to pressurize the empty gear case to no more than 10psi. Any suggestions on how to pressurize. I was going to attach a pressure gauge to the vent hole and use a bike pump (do not want to use a compressor) to bring the pressure up through the bottom drain and see if the pressure holds.

Has any one done this themselves, what different action would a shop take to pressure test a lower unit?

Thanks,

Kevin

[boats.net]

Best to just replace all seals in gearcase when water is getting in.