need help with my tilt trim 1997 50 hp mariner 4 stroke

the tilt switch on my throtle works sometime and sometime it dont when it doesnt work i can shut the motor off and i lose all power to my ignition it wont crank i can reach back on the motor and push the trim button and it works fine after i use this switch i regain power to my ignition any ideas

Sounds like you have a short somewhere which is one of the most difficult things to track down. It could be in your tilt switch, either on the control or on the motor itself since fiddling with this restores your power or the tilt relays may be shorting out - but it could just as easily be somewhere in one of the wires between "here and there".

Remove the hood and take a good look at all the wiring feeding/coming from the trim motor. Look for loose, corroded, damaged connections etc and repair/replace anything that looks even a little out of whack.

If all looks fine, then disconnect the battery, grap and ohm meter and start checking continuity of individual wires - one could have got pinched, so you need to move/shake them to see if something is not keeping connectivity when it's moved around.

And if this sounds like it could take a long time, it will (and probably longer than you even imagine unless you get lucky)....

Remove the trim relays and look for corrosion in and under the sockets.

where is the trim relay located

see #21 for reference...mounted on the starboard side of my engine http://www.mercruiserparts.com/Show...nbr=2853&bnbr=290&bdesc=Power+Trim+Components