Need an exploded view of parts of 1994 Yamaha 90 hp outboard trim and tilt cylinder oil reservoir valves, for re assembly.

Some grease on the end of the trim rams and see if it don't go away.

Low fluid level will cause it to fail to actuate and not go up or down, can also let it not hold position as well. Filling to proper leevel with specified lubricant is recommended. If you allow the level to go too low, the pump will pull air and could burn out.

Yes if you have lots of money

loosen engine mounting bolts and steering tube , trim engine up by releasing the valve on the side and tie up so not tocome down ! remove pin on the ram then remove all bolts and wires and should come out !

You have to remove starboard transom bracket,then remove circling from t/tilt release screw,remove screw,left hand thread.There is a flat washer that normally sticks to screw/valve,this needs to be replaced.Its easier to do this with motor trimmed up or if motor is off boat,lying on its side.Very little oil will come out if done in trimmed up position

Just pull them apart and clean.

no. a unmodified transom bracket may need to be moved not removed. Since the tilt motor is out you will need to manually lift the engine. you can see the picture diagram at www.yamaha-motor.com. click on outboard motors,parts and service, view parts catalog. find your year make and model by following steps listed at top. select power trim and tilt assembly. in the picture you will see the location of the Manuel release valve on the starboard side. turn the Manuel release valve then lift the engine. tie it up or use a stand to keep it up,do not use the tilt lock. with the engine in full tilt position, you can see the motor. some brackets are modified were you can remove the motor without moving the transom bracket. If unmodified you'll need to follow these steps. (1) lower the engine back down.the steering arm needs to be removed from the steering cable and swung forward. do not remove steering arm from engine. on the starboard side of the engine you will see the steering cable going into the steering cable tube. (2)a 1 1/6 nut secures the cable to that tube remove it and slide cable out do not remove it.(3) lift engine again and secure it. your about to remove the motor mount bolt so make sure you secure the motor completely (4)remove upper and lower transom to bracket bolts remove bolts on the port side only.(5) you will see three bolt that go through the transom bracket to the trim and tilt assembly. remove them.(6) if all bolts are removed you will be able to slide the port transom bracket to the left out of the way(7) remove tilt/trim motor.

To check the fluid level, tilt the motor up and engage the tilt lock lever. Open the bolt on top of the tilt/trim reservoir. The fluid should be even with the bottom of the bolt hole. If not add some fluid. When you put the bolt back in, run the trim up and down a few times. That should purge any air out of the system. Always be on the lookout for any leaking hoses or fittings. Hope this helped and best wishes.

Stop! Dont replace the pump...I would bet that it is the "down" Solenoid that went haywire. I would begin by replacing the Down solenoid...it is a far easier and cheaper fix and if your pump works to raise the engine then that tells me that it is not faulty. The Down solenoid looks just like a starter solenoid and the one that you are looking to replace has a GREEN wire to it. Yellow with a red stripe is for the starter. Blue wire is the up solenoid. So replace the one with the green wire going to it and I bet it will fix your problem.