I had a guy tell me once that his boat wouldn't steer while underway, it would turn freely at rest or on the trailer but the tiller felt like it was stuck in mud when he tried to turn.
I walked up to the boat and saw that the motor was missing the tilt/trim pin and the gear case was fairly close to the bottom of the transom, where there was a fresh looking shiny spot.
What was going on was that when he applied power, the motor was pressing against the transom, the av plate was just high enough and just long enough to make contact. I found a used pin, set the motor up two holes and all was good.
Of course a week or two later he showed up saying that his boat was getting slower every time he went out. He said it felt like it was loosing power and getting weaker and weaker. He had replaced both spark plugs and bought a new carburetor but it didn't fix it. I looked at his prop and it didn't have a single straight blade on it, I asked him what he hit and he said every since i put that pin in the motor the motor drags on the ramp and over some rocks where he fishes, he said before, it would just bounce over all that crap. I told him he could just unlatch the motor but that was too much trouble.
He was dead serious too. I did my best to try and explain how trimming up a motor works but I'm sure he was pretty much set on just taking out the pin and grinding off the part of the av plate that was hitting the hull instead. I never saw him again.
If the grease fittings don't take grease, take them out and clean them with some carb cleaner or acetone, soak the bushings with warm penetrating oil. I keep one of those steel sprayers around full of a mix of acetone and atf that I just set on a hot plate for a few minutes to get it good and warm, then I pressurize it and soak what ever needs to be lubed or freed up. Heat makes a big difference. Even taking a heat gun to the item your trying to lube can help just be careful some motors use plastic bushings.