Yamaha 150 Comes out of water????

[sailfisher96]

Hello all my 1999 ox66 150 has a problem... when I lay off the throtle at hi speeds the motor come up. Also if i give it gas in reverse it will climb up. When the boat is on the trailer I can lift the motor by hand there is no resistance or pressure. I have no leaks in the trim and tilt system. Is there a valve or sensor that controls this? Any input will be great! Thanks!!!

 

[99yam40]

Re: Yamaha 150 Comes out of water????

Does it go back down to where it was by itself or do you have to run the trim motor to get it to go back down?
Does it go up and down OK with the tilt and trim switch or does it seem to have air in the system?
You need to check the oil level if it comes back down by itself.
I believe there are some relief check balls and springs in the unit to allow the motor to come up if it hits something , but they should seal back off and hold the motor in the up position and you would have to run the tilt motor to lower.

 

[rodbolt]

Re: Yamaha 150 Comes out of water????

could be a failed shock valve on the tilt piston. the memory piston will allow the unit to drop back to where it was at the time of impact.
places to look are manual release valve,down main valve,shock valve,shock return valve,thermal valve,or the tilt piston orings.
its a 64e showa unit and is used by many brands of outboards.

 

[sailfisher96]

Re: Yamaha 150 Comes out of water????

Yes it comes back down by itself and there is no air in the line and the oil is full I think it may be an o-ring or that shock valve! I will have to take it apart and see. How do you access the shock valve?

 

[buddybarnhill]

Re: Yamaha 150 Comes out of water????

busted o ring in cylinder