Removing Lower unit 500 Help!!!!

[bigdpeter]

I have a 1981 Mercury 500 50hp I am trying to remover lower unit to service water pump. It won't budge at all. I suspect Drive shaft is frozen to Crank. Any ideas on how to free this without causing to much damage. Any advice would be greatly appreciated.<br />Many thanks<br />Dave

 

[KCLOST]

Re: Removing Lower unit 500 Help!!!!

Are ;you absolutely sure you have all the nuts are out. There may be one under the trim tab....<br /><br />There are two studs on the sides, I believe one under the trim tab, and maybe another...<br />Someone hopefully will correct me if I'm wrong...

 

[bigdpeter]

Re: Removing Lower unit 500 Help!!!!

Thanks for you reply <br /> yes there are 2 nuts on the side, and one bolt under the trim tab .the lower unit moves down about 10mm and stops there. If i put any levers between the faces the engine and prop become yery hard to turn over<br /><br />It looks more and more like a big job?

 

[studlymandingo]

Re: Removing Lower unit 500 Help!!!!

Unless you have some serious bearing issues in the lower unit, the crank is probably not frozen if the housing is coming down at all. Do you have the shift linkage disconnected?

 

[bigdpeter]

Re: Removing Lower unit 500 Help!!!!

shift linkage ? how do i disconnect

 

[Nos4r2]

Re: Removing Lower unit 500 Help!!!!

Ignore Studlymango, the merc 500 has a splined rotating gearshift linkage that comes apart on its own as you drop the lower unit.<br /><br />Shrink your avatar please!

 

[north40]

Re: Removing Lower unit 500 Help!!!!

That's a hell of a big avitar you have there!!!

 

[bigdpeter]

Re: Removing Lower unit 500 Help!!!!

Hopefully sorted the avitar out but the 500 well thats another story<br /><br />so far taken every thing of the 500 then removed from the boat and now in the garage what for it , now upside down with a gallon or 2 of parifin in the shaft housing and the 2 nuts pushing the lower unit up <br /><br />O and thanks for the help North40 i was getting Concerned

 

[joblo33]

Re: Removing Lower unit 500 Help!!!!

You might need to hammer a wedge into the crack to get it to seperate. I've used everything from a wooden doorstop to a large chisel for that, depending on what it takes to move it. By the fact that it dropped 10mm I'm guessing you got the other bolt too. There's one on the bottom of the anticav plate before the one under the anode.<br />Eric

 

[bigdpeter]

Re: Removing Lower unit 500 Help!!!!

Thank Eric <br /> <br /><br /> yea got that one , did you do much damage to the casing ?not worked on a boat engine before ,i do not want to damage the casings