I just purchased a 1986 century 3000 and the tilt will go down but not back up. I had to use the trailer button to get the drive to go back up. Any ideas on what this could be?

Is the drive an Alpha1? If so, there is a trim limit switch on the right side of the drive near where the drive pivots. It's round, about 2.5" in diameter and has a wire coming out of it. It's pretty common for them to fail. Sometimes you can take them apart and clean the contacts (get corroded) but usually that will only last for a few days. Replacement is a pain because the wire goes through the transom and it's a chore to remove and replace. Check it out though. Search "trim limit switch".

mine did almost the same thing but in reverse,
tthe down selinoid on the pump was bad, also
check the button for the trim i had the down
position go bad on a brandnew one .

I agree, before buying a new solenoid, he can switch the down and up solenoids, and see if the problem follows, if so ya know it is the solenoid

If it works with the trailer button, then its probably a bad trim sender on the drive.

Either the UP switch or the trim limit switch.

Thanks for all the answers! Ill check the solenoid and see f thats the problem. What is the easiest way to check if that is bad?

I'm about 98% sure its going to be a bad wire on one of the electric senders(puck on sides of drive) or the wire is disconnected inside the bilge.

Solenoids should be fine beings it still goes up with the trailer button.