I have a 1986 mercury 115 and need to replace the trim motor, how do i get it out/

FourStroke 150 hp - Mercury Marine

https://www.mercurymarine.com/en/ca/engines/outboard/fourstroke/75-150-hp/Mercury FourStroke outboard motors are incredibly powerful and efficient, and they feature a wide range of applications. Crafted for less weight and high displacement, they generate abundant torque and immediate power. ... 150 115 90 75. HP / kW‎: ‎150 / 110
Engine type‎: ‎8-valve single overhead cam ...
Dry weight *Lightest model available‎: ‎455 lbs / .

here you go

Mercury Optimax 115 Service Manual

115 hp

It's a 25XD from 1986

most of these will come off if you lift the engine to fully up and lock the lever up to hold it there ! Then you can access the trim motor , clean off around it then undo and remove the motor after disconnecting the wires near the carbs !

replace it as sounds like valve gone !

Find Mercury Marine Outboard Motor Parts by Engine Model

 Buy a replacement handle. Once you have it remove the door trim, remove the screws that hold the handle, unhook the command bars by rotating the handle and take it out. Mount it the opposite way.

I own a small Mercury outboard so I did alittle reading in the manual and the ratio for your 86' 115 HP is 50-1. Hope it helps. Coach Theune

Your motor is fine. It needs to put out more than 12 volts or the battery will not charge. Most alternators put out between 13 - 17 volts, so this is well within the range.