Re: 1979 Evinrude 175 HP Tilt/Trim Problem
Double check to see if the trim rams are being pulled in, leaving the engine in a full tilted position. If so, the following would pertain.<br /><br />(PTT Won't Drop Engine Until Trim Rams Retract)<br />(J Reeves)<br /> <br />From the extreme up position down to the trim rams, the engine drops via gravity. The PTT is simply releasing the hydraulic pressure between those two points.<br /><br />The usual cause of this type problem is that the tilt/steering tube is so tight due to corrosion (whatever) that it is holding the engine in the up position until the trim rams are pulled in.... then hydraulic pressure takes effect.<br /><br />The cure is to loosen one of the large tilt/steering nuts 1/2 turn, then with a 2x4 and a large hammer force the swivel bracket sideways slightly. Force grease into the grease fittings on the front of the swivel bracket. That should do it.<br /><br />However.... if the above does not pertain, either the unit is low on fluid or you do indeed have a hydraulic lockup, in which case.......<br /><br />(PTT Hydraulic Lockup)<br />(J. Reeves)<br /><br />If the engine has been trailered without having both of the trim rams pulled in, or trailered without even having the engine being supported by the trailering support, it is possible for the PTT to encounter a hydraulic lock up. The slight up and down motion, when trailering allows over 1700 psi of oil pressure to build up on the wrong side of the oil pump. Since the oil pump cannot exceed that 1700 psi, the unit is effectively hydraulically locked into position (the elec motor runs and does nothing).<br /><br />The proper method for trailering is to have the engine in a full tilt position and resting on the trailering support bracket, then have both trim rams pulled in to a point where the engine makes a jerking motion. At this point, immediately take your finger off of the PTT trim switch. Now, quickly and sharply, tap the PTT up button. This removes the vast majority of down hydraulic pressure but at the same time, the engine is solidly locked into position and cannot rock up and down.<br /><br />(The Cure)<br />Have the engine in the up position and supported so that it cannot fall. Look straight at the PTT assy.... you will see what looks like a large slotted screw on the port (left) side of the PTT assy, but which is in fact a check valve. Remove that valve and what you find inside which is a shuttle valve, and a spring on each end of that shuttle valve.<br /><br />After you've removed those items, look straight inside of that chamber. You'll be looking at the reverse side of another check valve. Look at the hole in the backside of the valve you removed. You will need a punch that will fit inside of that hole.<br /><br />Now, place the punch inside of the hole in that check valve that is still in the unit, and tap it rather sharply with a hammer. It will take quite a rap but the idea is to unseat the valve to release the hydraulic pressure. Watch your eyes as when you do release the pressure, it will have a tendency to spray out somewhat.<br /><br />After releasing the pressure, reassemble the shuttle valve, springs, and outer check valve. Fill the oil reservoir with PTT fluid, having the engine in the extreme full tilt position. That's it.
