Im posting this question for a friends boat.He has a bass boat with a late 80s 150 mariner motor.The problem is his trim motor.It will trim down but wont trim up.Im sure this is probably a common problem so is it the motor itself or a switch or fuse.He lives far away so I havent had the chance to look at it myself.Im a pretty good mech. but have never looked at a diagram or tinkered with a trim motor on a boat.Thanks