I have a 2004 40HP 4-Stroke yamaha with Gas assist and am looking for help on setting the Trim. After reading the manual it said that I can set the trim simply by flicking the trim lever up while stopped, lift the motor to desired trim, and lock the lever in the down position. The mechanism holds well but once I place enough power on the prop to get the boat up on plane, the force of the engine presses the motor back in the bottom position. Is this normal or is there a defect?<br /><br />Thanks
