I have a problem with a '87 Yamaha tilt trim system. The motor settles to the trim stops in about 20-30 seconds and will not maintain trim when in use. The rams piston seals are OK, the bypass valve is closed and fitted with new seals, the psv seems OK, the shuttle valve is fitted with new seals. The only thing I can think of now is oil - perhaps the wrong grade.... any body had this problem?
