merc Lower unit removal STUCK!

[surphrat420]

i removed the two nuts about 3/4 the way back on the LU and i removed the trim tab and bolt under that, I removed the nut on the single bolt that comes up out of the front of the LU, and I lossened the two nuts that are up towards the front of the LU (they wont come off until the lU drops more)...OK so.. I heated the front of LU, bang it with rubber mallets ,wood and pryed with pry bar between two halfs. The back with seperated about 1/2but the front will NOT move, and its been soaking in liquid wrench all day! <br />oh yes this is a 25" shaft and im trying to seperate it just below the Leg and the top of the "long shaft extender piece" but it does not seperated there or at the seperation below the "extention piece"<br /><br />ANY HELp...or should i just beat the living day light out of the front bolt (as i've read it can be replaced, casue its just a stud.)<br /><br />thanks again...

 

[Nos4r2]

Re: merc Lower unit removal STUCK!

How old is your motor and is it still on the boat?<br /><br />It's probably not the bolt that's the problem-more likely if it's an old motor to be the driveshaft/powerhead joint frozen.Older mercs dont have a plated driveshaft at the join so they do seize. My trick was to turn the motor upside down in a big tray and fill the leg with as much diesel as possible(it's an excellant penetrating lubricant as it's thinner than most WD40 type stuff) then leave it for a week-keeping on topping up the diesel in the leg.<br /><br />BE AWARE that if you do this you'll get diesel in your engine thru the exhaust ports so make sure you turn it over for a while with the PLUGS OUT before trying to start it.This is to clear out the diesel. You'll quite possibly hydraulic lock the cylinders and trash the motor if you don't-but it worked for me on 3 junkers I've split like it. <br /><br />Make sure when you put it back together that you coat everything with a load of anti-sieze grease too.

 

[KCLOST]

Re: merc Lower unit removal STUCK!

Model of motor?

 

[surphrat420]

Re: merc Lower unit removal STUCK!

Its a 85 200hp black max<br />Im pretty sure its the most forward single bolt,( that ive been told is a stud that threads into the LU at the other side also). Well today i hammered the bolt and it went down about 3/4 inch untill it was flush with the hole! so now the whole LU is down even about 3/4 or 1 inch down, and wont budge. In the morning i might fabricate a air chiesel head with a produrding shaft the same diameter as the bolt and see if i cant air hammer it out any more.

 

[surphrat420]

Re: merc Lower unit removal STUCK!

PS im gonna post s few pic's <br />It dark already but there coming in a few....

 

[surphrat420]

Re: merc Lower unit removal STUCK!

well here are some pics i dont know if they help.<br />also I might mention that the pice just below the seperation, the "long shaft extender leg" is will slide up and down on the studs (at least the 1/2 inch the LU has droped)<br /><br />thanks again <br />hopeing not to have to cut the stud off!<br />

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[sealyons]

Re: merc Lower unit removal STUCK!

I had the same problem with a smaller merc outboard and it managed to get it off by placing a 2x4 on the fin and giving it a couple good whacks with a 15lb sledge. 2 or 3 good hits and it came right off.

 

[surphrat420]

Re: merc Lower unit removal STUCK!

ok ill try that...I went at it witha rubber mallet but was afraid to hit to hard, but I guess the 2x4 will distribute the force along the whole fin, and besides, who really needs those fins anyways <br /><br /><br />PS KEEP UM COMING PLEASE! Im gonna try every thing first thing in the AM before cutting throught the stud

 

[surphrat420]

Re: merc Lower unit removal STUCK!

Got it!!! just use the old Air Chiesel and a few strips of metal and used it between the two halfs!

 

[Bob H.]

Re: merc Lower unit removal STUCK!

When you put it back together put a light coat of grease on the main shaft slines. Not too much grease or it will get air bound during reassembly.

 

[dodl]

Re: merc Lower unit removal STUCK!

Hello,<br /><br />Can you explain whats an Air Chisel, and how you used it? <br /><br />I have exactly the same problem like you, already damaged the lower unit with hammering, tried wedges, but nothing. No chance.<br /><br />I just need the powerhead, so i could also cut the driveshaft. But then it still sits in the crankshaft.<br /><br />thanks<br />martin

 

[surphrat420]

Re: merc Lower unit removal STUCK!

the air chiesel is really an air hammer i guess.<br />Its a pnuematic (air operated) hammer. Mine looks like a impact gun (the tools the tire place uses to take your lug nuts off),but it has a removable "bit"<br />the bit i used....well im just gonna take a picture and post it for you, below is the chiesel and bit used. The tip is small enough to get it between the very front of the LU right near the "align pin" that sits in near the front then just work it in all the way, until it gets all the way up to the largest part of the shaft (the round part near the gun)<br />Once the unit was down about 1 1/2" then I used a large pry bar to "fill up" the gap then just reiserted the air chiesel in the same way to compleatly remove the unit. <br /> <br /><br />Good luck!<br />

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