I resealed the lower unit on my 1962 28 hp Johnson outboard today, and then did a pressure test. The pressure tester is a bit crude, and consists of some air-fittings, hose, old pressure gauge, and a syringe. The pressure gauge is a bit sticky, so doesn’t show small pressure drops very well.
I put approx 7psi of pressure into the lower unit and left it for 1 hour, with no sign of a pressure drop on gauge. However, when I spray with some soapy water, there are some extremely small bubbles coming out of the two small holes used to punch out the prop shaft seal. There were no bubbles from around the prop shaft, which tends to indicate a very small leak between the prop shaft seal and housing. I’m going to leave the pressure tester on overnight and see if the lower unit holds pressure. I don’t think the leak would be enough to let water into the lower unit, but will seek the opinion of the experts.
I put approx 7psi of pressure into the lower unit and left it for 1 hour, with no sign of a pressure drop on gauge. However, when I spray with some soapy water, there are some extremely small bubbles coming out of the two small holes used to punch out the prop shaft seal. There were no bubbles from around the prop shaft, which tends to indicate a very small leak between the prop shaft seal and housing. I’m going to leave the pressure tester on overnight and see if the lower unit holds pressure. I don’t think the leak would be enough to let water into the lower unit, but will seek the opinion of the experts.
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