How much force can I use without damaging my crank?

[Nos4r2]

How much force can I use to remove a the L/U when the driveshaft is siezed to the powerhead without damaging my crank on my 50 blueband?<br /><br /> It's been upside down hanging from the skeg and full of penetrating fluid for 3 days now and no sign of it shifting even with nearly half a tonne of weight pulling downwards.It's moved the usual 10mm and stuck at that. I don't want to have to buy another engine...

 

[nos1013]

Re: How much force can I use without damaging my crank?

Are you absolutely sure you have ALL the bolts out?<br /><br /><br />"I have not failed. I've just found 10,000 ways that won't work." Thomas Edison

 

[Nos4r2]

Re: How much force can I use without damaging my crank?

Yes.

 

[AndyL]

Re: How much force can I use without damaging my crank?

Have you tried pulling it back up that 10mm on the bolts then working it back down, carry on until the penetrating oil gets into the problem and it may just work itself slowly out. Its one of those awful problems that you cannot leave as is. If nothing you have my symapathy as I could never get the powerhead off my 135 due to corrosion in the studs.<br />The best of luck.<br />Andy

 

[LubeDude]

Re: How much force can I use without damaging my crank?

Where and how did you put the penetrating oil in.

 

[Nos4r2]

Re: How much force can I use without damaging my crank?

Andy, yes. BassinLubedudeguy, drilled a 5mm hole in the side of the leg near the driveshaft/powerhead joint and squirted it straight in onto the joint. I WAS going to tap the hole out to m6 and put an allen bolt in it to seal it.<br /><br />It still ain't shifting.

 

[Motor Boater Bill]

Re: How much force can I use without damaging my crank?

Wooden shims tapped into the space between the leg and the LU are often recommended. I have also heard the following procedure described, although I have not had to do it myself:<br /><br />Put the nuts back on, but leave them loose by about a quarter inch. Put your motor on the boat, back it down a ramp into the water, with the boat secured to the trailer. Then fire up the motor and shift it back and forth from forward to reverse until the LU comes loose.<br /><br />If you read enough posts on this board I think you will find some discussion of this by persons who have tried it. Sorry I can't give you any personal experience on this. I did have a LU once that I bought and one stud was so corroded that the guy I bought it from had simply cut that part off of the leg to get the LU off. I heated, soaked and beat on it for days, and finally got it out of the hole in the LU. I can't imagine what it would have taken to get that stud loose if the LU had still been connected to the leg. Salt water. But, if your LU is dropping a little bit, then it does sound like the shaft and not the studs. Good luck.

 

[Motor Boater Bill]

Re: How much force can I use without damaging my crank?

Missed the "still ain't shifting" at the bottom of your post. If it is in gear, the above technique might still work.

 

[gungalunge]

Re: How much force can I use without damaging my crank?

what about the bolt under the zink thing . have a look under there ...

 

[gungalunge]

Re: How much force can I use without damaging my crank?

just above the prop

 

[Nos4r2]

Re: How much force can I use without damaging my crank?

If you can stretch a bolt that big by 10mm gunga .... <br /><br /><br />Tried to remove it again today. It's not going to come off. I broke a 2-ton ratchet strap in the process-and yes, I was pulling square.<br /><br />Time for a new engine methinks.

 

[Motor Boater Bill]

Re: How much force can I use without damaging my crank?

Drill a bigger hole in the leg and cut the drive shaft--then get a new drive shaft or a new LU.

 

[Chinewalker]

Re: How much force can I use without damaging my crank?

Try unbolting the powerhead, followed by dropping the motor on it's side. Yes, dropping it. I've done this a few times and it's broken stubborn shafts free with the sideways shock. Lay a thick blanket on the floor first as you (obviously) don't want to cause more damage. Lift the powerhead end up about a foot and let it go. Repeat as necessary, and try it from both sides.<br /><br />- Scott

 

[Chunder06]

Re: How much force can I use without damaging my crank?

Motor Boater Bill has the correct answer, this is the only way it will come out, cut the shaft with an oxy torch but you can bet the spline will be buggered but there is a fix for that as well.

 

[Nos4r2]

Re: How much force can I use without damaging my crank?

It's not worth what it'll cost to repair now. I've actually got a spare stainless driveshaft but I really don't think an 80's lower unit is likely to seal again if I strip it. It's been in salt water all it's life.<br /><br />Hopefully got a yam 55 on the way now