View Full Version : Lower unit pressure test

09-17-2006, 02:07 PM
"What is an exceptable PSI for a pressure test on a lower unit. Bought a used lower unit with 90 warranty and was sold as passing a pressure test. I tested the unit before I insatlled it and it would consistantly hold 10-11 PSI. Is that good or too low. lHave heard of others saying 15+ was correct.


Donnie Strickland
09-19-2006, 05:30 PM
The Yamaha spec is 14.7 psi.

09-19-2006, 06:31 PM
"Is 11 psi acceptable?

how many fluid ounces of lower unit oil should it hold. I thought I put close to a quart in it before I ran it about 50 miles last satruday. I let it sit for about 48 hours and drained the oil. It was clean and clear, but only got about 19-20 ounces back. If I did put close to 32 ounces in it and only had 20 after a 50 mile run then I've got a leak somewhere and I sure didn't find one and believe me I LOOKED for one.

09-29-2006, 12:55 AM
u need to pressure check
u need to vaccum check
10 psi for at least 5-10 mins