1985 Mercury Outboard V-300 V-3.4L Shop Service Manual, Page 196Get this manual
POWER TRIM DESCRIPTION
1Th Power Tri system consists of the powe trim pump (contain electric motor, oit reser voirand oil pump), trim cylinder (moun ted on the engine), and hoses which connect th power trim pum to th trim cylind er 2Th rem ote control (or trim panel) is equipped with swi tches thai are used for trimming the ngine "up" anddo wnwhile engi ne is under powe r, and trai ler switch thai is onl used to lilt engine up for trai lering or shallo wat er operation al idle speedmoto will dri ve the oil pu mp and force oi in to thup" side of the trim cylinderThe traile ring ci rc uit bypa sses th trim limit switch so that th engine ean he tilt ed up fo trailering, or shallow wa ter operati on SeeWarning", foll owing
AWARNING
1DO NOT operate engine above idle RPM when engine is trimmed beyond trim limit cut-out point as the swivel bracket will have no side support and may break2Excessive engine trim angle will result in Insufficient water supply to water pump causing water pump or overheating damageCheck that water level Is above gear housing water Intake holes whenever engine is running