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Help! Gear Case won't come off!

T

tkeefe

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Hello, I have a (new to me) 2001 mercury 90 EPLTO (SN) 0T183215, Model 1090412YN. I need to replace the water pump. I've taken off all 5 lock nuts. Two on each side plus one in the back by the trim tab. They came off easily with no issues. The gear case will not budge though. No movement at all! Not even a little!! I've hit it with a rubber mallet, Used a piece of 2x4 on the cavitation plate and hit that with a hammer. I sprayed liquid wrench all the way around and in the stud holes. I tried to separate it with a sharp wood chisel. I ran the trim all the way up and tried a bottle jack against the transom with some wood pieces as buffers, but nothing. I was thinking of trying some heat. Any other ideas?
 
I own evinrude products and they have 6 bolts to take out so idk about the 5 but there is a shift rod that goes up just underneath the block by the carbs you have to take that bolt or nut out there for it to come down and I personally wouldn’t have done any of that stuff if you can’t just stick a screwdriver in and turn it and the gear case doesn’t come down reasses the situation something is holding it and lower units are not cheap or easy to replace. Hope this helps
 
I do not believe there is a shift rod disconnect below the carburetors on that Mercury motor.----No need to send the owner looking.-------Perhaps the driveshaft is rusted into the crankshaft spline ?
 
Right, the Mercs just drop down. Is there another capscrew on this one hidden under the trim rudder? I didn't look at the schematic.
 
No I don't see any others. I did get it to separate about 1/16 - 1/8" last night. I drove a bunch of shims in and sprayed the crap out of it and let it sit till tonight when I get home.
 
Is this a fresh water or salt water engine.?

There is not much you can do if the spline of the driveshaft is so to say frozen or rusted in the power head. Do what you are doing. If it has dropped a little bit. Would be best if the motor could be turned upside down. That way you could get penetrating fluid down to the spline. But being a 90hp. You would need something tall to lift it. There are dowel pins on the lower unit that may be the culprit also. If you get it off. Please put marine grade grease on the spline before you get it together.
 
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I finally got it to come off! Gears look fine. It was a build up of sand inside the stud holes that was like concrete! I used a drill to get the sand out.
 
Nice job, I have an assortment of oak wedges. Don't like to scratch paint either. Take off lots of lower units as I do aluminum welding. Rocks are my good friends.
 
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