Lower Unit removal classic 45 #OB121232

[halmc]

Cant remove the lower unit of this motor for water pump service, I have the SELOC manual for the motor.

After removing the trim tab and the nut it hides, I also removed the nut from the bottom (7/16" stud) and loosened each nut ((5/8" hex) on each side of the exhaust housing. In other worlds, I've removed four large fasteners and nothing else.

I have not disconnected any aspect of the shift mechanism, that is often necessary on outboards (?)

At this point the SELOC manual cautions me as to the lower unit's "falling" away.

LOL, not only will mine not fall, but no amount of careful prying, and even using the two nuts on each side of the exhaust housing as "pushers" has managed to persuade the lower unit any more than about 1/4" away from its resting place.

In fact I have applied enough withdrawal pressure to the lower unit that I am afraid of breaking something.

Have I missed something?

Suggestions much appreciated!

 

[mthieme]

Re: Lower Unit removal classic 45 #OB121232

No, you haven't missed anything.
It sounds like the drive shaft is stuck. Sometimes they can be stubborn. Sometimes it can get really ugly.
Keep working it.
You might want to search on "stuck shaft", but some of the posts can be discouraging.
When and if you do manage to get it out...make sure to grease the splines at the end of the shaft for next time.

 

[Laddies]

Re: Lower Unit removal classic 45 #OB121232

You havn't missed any thing, it's either stuck on the drive shaft or shift shaft. Get some onr to watch under the carb to see if it,s the shift shaft or the driveshaft. Good Luck

 

[halmc]

Re: Lower Unit removal classic 45 #OB121232

When and if you do manage to get it out...make sure to grease the splines at the end of the shaft for next time.

If only you had advised the DPO (distinguished prior owner).

I have even tried loading it up with plenty of force and spinning the engine with the starter. No soap.

What eventually breakes when a fellow gets REAL serious about getting it off?

 

[BR]

Re: Lower Unit removal classic 45 #OB121232

I had the same difficulty removing the lower unit from my '76 850. Turned out the shift shaft linkage had corroded and siezed up. I placed a number of wooden shims in the gap on opposing sides of the gearcase and little by little drove them in, expanding the gap. Eventually the shift shaft gave way and pulled out of the lower unit completely but the lower unit came off. If that happens to you, don't panic...there is a thread on this forum to solve that and it's not as daunting as it may seem. I was surprised at how stubborn it was and how much effort it took to remove with only the 5/16"? dia. shift shaft holding it together. The wood shims worked great and did not damage any of the castings. I do not recommend leverage or prying tools for this job...let the wedges do the work!

Good Luck!

 

[halmc]

Re: Lower Unit removal classic 45 #OB121232

I had the same difficulty removing the lower unit from my '76 850. Turned out the shift shaft linkage had corroded and siezed up. I placed a number of wooden shims in the gap on opposing sides of the gearcase and little by little drove them in, expanding the gap. Eventually the shift shaft gave way and pulled out of the lower unit completely but the lower unit came off. If that happens to you, don't panic...there is a thread on this forum to solve that and it's not as daunting as it may seem. I was surprised at how stubborn it was and how much effort it took to remove with only the 5/16"? dia. shift shaft holding it together. The wood shims worked great and did not damage any of the castings. I do not recommend leverage or prying tools for this job...let the wedges do the work!

Good Luck!

Trouble is, I've long passed the point at which wooden wedges would do anything -- I'm into the realm of chisels and ball pien hammers.

Even with this brutal strategy, I've extracted the shaft, or to be more precise, extracted the lower unit only about an inch.

The engine spent most of its life in salt water. The union between the drive shaft and the receptical into which it fits is likely rusted into one lump.

Can anyone say how far the drive shaft fits into the bottom of the crankshaft? That is, I've got about an inch out, how far I got to go?

 

[Yepblaze]

Re: Lower Unit removal classic 45 #OB121232

At 1 inch you are nearly there.

Get or make bigger wedges.

 

[halmc]

Re: Lower Unit removal classic 45 #OB121232

There's good news and bad news.

The good news: I was able to remove the lower unit.

The bad news: The shaft didn't come with it.

The wedges, including the larger and larger ones worked well enough, but the lower unit is not designed for that kind of load and the shaft pulled out of the lower unit, leaving considerdable mayhem in its path.

Mindful that there wouldn't be much use in finding a nice used lower unit (assuming the present one is destroyed) unless I managed to pluck out the drive shaft, I eventually got the shaft out, but OMG was it ever in there good.

Unfortunately, I suspect I'm in the market for a good used lower unit, as the exit of the shaft was not graceful.

Here's an image of the "successful" technique for extracting the shaft from the power head and a link to some other images of my day, which wasn't exactly a day at the beach. Here's the link to the saga: http://s274.photobucket.com/albums/jj271/halmca/Merc/

And here's the image:

 

[halmc]

Re: Lower Unit removal classic 45 #OB121232

At 1 inch you are nearly there.

Well, yes and no. The inch didn't come from where you and I thought it came.