Mercury 75hp Power Trim and Lower Unit problems

Glad I found this website. Learned a lot in last couple days already. I bought a 1986 skeeter F-80 boat that was in great shape but the 75 hp Mercury 3cyl motor needed some work. The lower unit gears were trashed so I bought a rebuilt lower unit and thought everything installed smooth but when I fire the engine up the propeller turns also. When its not running I tried to turn the propeller and it will turn clockwise but make a clicking sound. Won't turn to the left at all. Shouldn't the propeller be free to turn both ways? Should I remove the lower unit again and try to line the shaft up differently? Any help on this would be greatly appreciated.
2nd - My power trim doesn't work. When I hit the button it makes noise like the motor is running fine but it won't go up or down. Anyone got a couple of steps I can check into to? I have just ordered a Mercury manual for it but you guys expertise would be helpful too! Thanks!

Re: Mercury 75hp Power Trim and Lower Unit problems

well seems like the problem with the lower unit was when u put it on either it wasnt in neutral or your controls weren't in neutral. see if you can shift into forward or reverse and see if u can spin prop in both directions. if it does leave it there then remove it and your lower unit should be in neutral. happened to me to when i changed my impeller. as for the trim start with checking fluid level.

Re: Mercury 75hp Power Trim and Lower Unit problems

Thanks for your help. That was it. I put the shifter in reverse and it ended up being in neutral. Thanks again.

Re: Mercury 75hp Power Trim and Lower Unit problems

Never instal in reverse with the unit up!!! you will damage the Reverse Cam for lockdown in reverse

Re: Mercury 75hp Power Trim and Lower Unit problems

So does anyone know the best way to correct this problem. Should I leave the shifter in reverse which is neutral to the lower unit and remove the shifter cable and move it back to neutral and then hook the cable back up or does this require me to actually remove the lower unit again and have to turn the shaft? Thanks!

Re: Mercury 75hp Power Trim and Lower Unit problems

You have to drop the LU, realign the shift shafts and then reinstall. All the manuals will tell you to install the LU with everything in FWD, but thru experience, it is much more certain to install with everything in neutral.

You will need to rotate the lower shift shaft to find neutral in the LU. Use a 7/16" socket (I think) over the end of the shift shaft splines and rotate CCW (do not rotate CW). It is spring loaded so there is a fair bit of resistance. You will feel three distinct positions FWD, Neutral and REV. FWD will have a lot of freeplay (about 120 degrees), neutral will be a very distinct detent, and REV will have a little freeplay. The shift shaft is free to rotate 360 degrees so you can continue rotating CCW if you miss the mark the first time.

Place the control in neutral and then reinstall the LU. All should be good.