Stuck Merc 90 Lower Unit

Hey fellas. I have a yr 2000 90 HP carbureted 4 stroke Merc outboard. The problem is that the lower unit REFUSES to come off. The motor is new to me and since the pee hole is not peeing with the hose on, I decided to replace the impeller. I hav the SELOC book and followed instructions. Tried a hammer (i know its a bad idea), tried PB Blaster penetrating catalyst, tried a wood wedge, then searched the forums. I would have tried to use my weight and muscle it, but the motor is on a flimsy wooden stand I built, and I dont like the idea of a 390 lb motor in my lap. Does ANYONE have any good ideas? Thanks in advance, this is my first boat and I'd be LOST without this forum!!!

Re: Stuck Merc 90 Lower Unit

Did you get the bolt hidden under the zinc tab by the prop? I forgot about it, and f*****D with it for half an hour before I realized my error.

Ian

Re: Stuck Merc 90 Lower Unit

Hey Ian thanks for the idea. I actually took the trim tab off three times thinking that the first time I took it off, I didn't look for the bolt thoroughly enough. Each time I removed it I saw the same thing.... Nothing... According to the book there are 5 nuts holding it on. 4 on the sides of the gearcase, and one under the anti cavitation plate. I have removed all, and it still will not come down more than a millimeter.

Re: Stuck Merc 90 Lower Unit

welcome to our world - the driveshaft is probably somewhat siezed in the crank - 10 years is a long time to not have them apart - if your up to it i have found it is easier to pull the engine block off - just make sure you grease the driveshaft before re-installing it and pull it apart at least every other year - salt water is nasty - i have seen many go thru my buddies shop that he has to cut the driveshafts thru the mid section and yet some still wont come apart -they are so badly siezed into the crank and it just gets more and more expensive .on the other hand lots of motors go 15-20 years on the origonal impeller - just depends on how shallow of water you drivie it in and the hours you run full throttle .

Re: Stuck Merc 90 Lower Unit

Well I appreciate the insight but I have succeeded at removing the lower unit, but it came at a price... A friend recommended using a dead blow. It worked, but unfortunately the force cracked off the the piece that was seized to the stud by corrosion. It was incredible how much corrosion there was. Here is a pic of the piece that cracked off. I think I will try to repair with JB Weld.

Re: Stuck Merc 90 Lower Unit

your best option would be marine tex - it will cure hard as steel .

Re: Stuck Merc 90 Lower Unit

verado7- I will keep that in mind for the next time I break something ...
For now I have already used the JB Weld before I read your reply. It looks as though it should hold well.. Here's a looksy....

Re: Stuck Merc 90 Lower Unit

and its not just for marine stuff , you plug holes in steel with it ,drill it ,tap it and thread a new bolt in -and it will be just as strong as before .