Trim and Tilt doesn't raise under the thrust of the prop

[CaptainDavidM57]

Help! After two years I put my 2009 Bass Tracker 75hp Optimax motor in the water. Prior to launch I ensured that the trim and tilt reservoir (it does leak a little) was full. On land the trim and tilt raises and lowers just fine. When I launched the boat and drove off at 3 to 4 mph the trim and tilt works fine. However, when I throttled up the engine the trim and tilt would not raise. Also, if I would stop while in the water and raised the engine as soon as I gave it the throttle the engine would lower and I can’t get it to raise while throttled. I took the boat out of the water and the engine lowers and raises just fine. I raised the motor and tried to push it down with my weight and it didn’t budge.
Why won’t the engine raise under the thrust of the prop?

 

[Scott Danforth]

you probably have crud in the hydraulic oil preventing a check valve from seating or you have a bad pump or weak motor

 

[Chris1956]

You are only raising the motor to the trim limit, right? She will not raise higher that that under any serious thrust.

 

[Scottsdale816]

I am having the exact same issues with my 50 hp. Hope someone can help.

 

[The Force power]

I am having the exact same issues with my 50 hp. Hope someone can help.

That great!! read this first;
https://forums.iboats.com/forum/eng...ow-to-get-the-best-results-from-your-question

 

[Dukedog]

what Chris says.. "tilt" rod will not hold anything over a touch off idle.. only shorter "trim" rods will........................

 

[Texasmark]

Quoting a 1996 sales brochure, Merc. PTT systems "Tilt" from - 4* to + 75 degrees while the "Trim" is only functional from 0 to + 20. So, if you have a significant pitch to your transom, don't expect much "Trimming out".