75 evinrude 115 tilt & trim problem

[scout15246]

I have a 75 evinrude 115 outboard motor with a prestolite tilt & trim. The problem that i am having is this: the motor goes up and down fine. Except on take off, i will have the motor tilted up. As soon as i take off the motor will drop all the way down. And i can not trim it back up until i am almost stopped. Then i can move it up and down easily. i have bled it several times, but no success. Help!!

 

[Joe Reeves]

Re: 75 evinrude 115 tilt & trim problem

Scout.... If that unit is indeed a PTT unit and not a straight Power Tilt unit, and it is the type that has a long cylinder located outside of each engine transom bracket, I would suspect that the "Stem Valve" assy, which is located at the inside bottom of the starboard (right) cylinder, has failed.

 

[ledgefinder]

Re: 75 evinrude 115 tilt & trim problem

As Joe says, many of the early OMC systems are just power tilt. They're not made to allow, or hold, trim adjustments under the higher loads of full-throttle. The power tilt-only systems allow you to raise the motor for mooring, or for motoring through the shallows at low throttle settings. However, at high throttle, the trim is defined by which set of holes you've got the trim crossbar in.