Were do i put hydraulic oil in my honda 75 outboard motor

Too much oil in a four-stroke engine can cause too much pressure in the crankcase and force oil out of the crankcase breather or past the seals that normally keep the oil inside the motor. This can leave oil outside the engine which then slowly continues to wash off into the water.
Clean the outside of the motor (inside the external casing) with rags and/or degreaser and lots of water to remove residual spilled oil.
Recheck oil level again after running the motor.
If the over-pressure was very high it's possible that a seal is damaged and will continue to leak after the oil level is corrected. If this is the case you might be able to see freshly leaked oil somewhere (after running the motor) to find what needs fixing (e.g. a new gasket or seal may be needed).

Hydraulic fluid is most likely low. Refill it, then work the motor up and down about four or five times. Recheck and refill reservoir. Run up and down several times until you get a smooth up and down motion. Recheck /refill. Any air in the line will work it's way out on it's own. Be sure to look for any leakage.

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 / .

I suppose you mean the oil in the Trim system...

Lift the engine all the way up,
Place the jackstand to keep the engine fully up.
You'll see a plastic plug in the center cylinder.
Unscrew that plug. ( There can be some pressure, take care of your eyes!)
Fill with ATF-oil till the level is at the bottom of the plug hole.
Screw the plug back in.
Lower the engine.
Done!

• 10w30 hd motor oil

50:1 But if your doing mostly low rpm cruising (trolling) then you could reduce that a bit to 75:1 to help reduce smoke. If you do mostly mid to higher rpm cruising, then 50:1 (1 pint to 6 gallons. )
Or 200mls in 20 liters if your Canadian.

Take out filler plug and turn upside down

50 litres petrol:1 litre Outboard TCW3 OIl
100litres petrol:1 litre Outboard TCW3
@ 50:1 You Would Put 240Mls Oil In 12 Litres Petrol
@ 100:1 You Woul Put 120Mls Oil In 12 Litres Petrol

you need to find your drain- fill screw get trim oil with a pointed tip cut tip to fit tight fill oil with trim up once filled turn bleed screww and lower motor fast once down tight bleed screw fast use trim switch to raise motor and bleed again do this 2-3 times and u should remove all the air comment me back if you have any ?s

if its an outboard you will see a reservoir near the cylinder on back, be careful and set the shallow drive lever so the weight is off the hydros when you open it, there can be up to 3000psi if it has weight/pressure on it

once added you have to blead air bubbles, go up then down at least 10 times

also a boat parts store(phone book) may be able to help you