78 merc lower unit

[mc66]

lower unit on 78 Merc, 20hp/200 is stuck. I believe the shaft is rusted together. Somone mentioned to take the power head off but if they are stuck together how is this done? Any ideas or suggestions? Thanks.

 

[Jacket4life]

Re: 78 merc lower unit

I read a thread on here about a guy hanging weight on the lower unit and spraying PB Blaster into it everyday and it eventually turned loose. He had a picture of it seems like it was suspended from a tree limb or a frame (I remember it was outside...) with a platform he made out of plywood chained to the lower unit and a couple hundred pounds of iron stacked on the platform. That's the only advice I've seen about it. I can't even remember the thread, don't know what to tell you to search for though.

 

[mc66]

Re: 78 merc lower unit

Thanks Jacket4life. Where would I go about spraying the crank if I can't see it? Any way to access it? I don't know of any.

 

[Wingedwheel]

Re: 78 merc lower unit

There was also a post on here awhile back with pics. The guy actually had to cut holes in the drive shaft cowling. He must have been good with a heli-arc though. In the end you couldn't tell. Anyway I believe he did this to get heat to the coupling to the powerhead.

 

[mc66]

Re: 78 merc lower unit

wingedwheel i saw something about that no pic's can't get clamp off. do you know how? seloc ng need shop manual. i think round rubber mounts come out removed snap rings just now soaking one side at a time try tomorrow or drill sm hole between clamp and base spray and hope for the best thanks mc66

 

[mc66]

Re: 78 merc lower unit

thanks for your suggestions hung it, beat it, cut it, and two cans of pb blaster nothing .about a month later walking by to get lawnmower gave it a grudge shot with a near by hammer a bam it came off bought another motor for parts and reassembled thanks again mc66