1979 mercury 200 20hp lower unit will not seperate! help!

I am trying to repair the water impeller and housing and put all new seals in for some one but I can not get the lower unit to separate from the mid section on a 1979 mercury 200 20hp 2cly. all 4 bolts are removed and it is the rotary shift shaft so there is no linkage to unbolt. I have been soaking it with krilo oil for two day and I have it hanging upside down from a strap on a engine hoist and a strap around the power head hooked to a ring in the concrete floor with tons of pulling pressure and banging on it with a hard plastic hammer for two days now and I still can't even separate the two haves. I can't even get a thin putty knife in between. can any one help that had this experience? I have changed a lot of impellers in my time but I never had one suck this bad. please help!

You removed the bolt hiding under that sacrificial trim tab?

Jeff

yes I did all bolt are removed.

Good idea using the hoist and the concrete floor.----------I would suspect that it should come apart with that technique.---------Use a bit more force as something should give here.

Okay I will give that a try. Good idea with the tethering with the rope I will do that too. I can see that the back stud where the shift shaft spline meats the plastic connector that stud had white corrosion around it. I picked as munch as I could out with a hooked pick and keep soaking it with krilo oil. The other studs seem like they are free But I really think that the drive shaft splines are rusted in to the power head badly. I have been pouring krilo oil down threw the middle stud and i can access the water pump housing threw the flush port with a straw spraying oil into that also. I can see all the penetration oil dripping out of the spark plug holes but I still don't know if the drive shaft is getting any of that oil. I want to try to not drill a hole yet if it was my motor i would of drilled it already.I have not tried it with the 2x4 yet. just banging on it with a hard plastic hammer but I am worried if I smack it to hard I will crack it. so I will try the wood thing tomorrow with heat and I will let you know if any progress or not. Thanks for the help.

Looks like the splines in the power head are rusted together.

One way to get them apart (if they WILL come apart) is this: Put the front nuts back on very loosely and fire it up in a barrel of water large enough to put it in gear. That often breaks 'em loose.

Jeff

Return it to the owner !!

That'd be quitting!

Jeff