1978 Mercury 20 hp lower unit stuck

Hello,

I have a 1978 Mercury 200 (20hp) that the water pump is shot. I have been trying to remove the lower unit from the leg to replace the water pump. I have removed all the bolts and nuts from the leg and tried to wedge the lower unit*off but it will only move about 1/8" or so. I am pretty sure that the top of the*drive shaft is rusted into the bottom of the engine and will not let the*lower unit drop out. I drilled a small hole (3/16")*in the leg and hung the engine upside down, and been spraying penatrating oil on the shaft so it will run down and help free the stuck shaft. After doing this over days, I have been lifting the engine up and dropping it, so that the weight of the engine will break the shaft free from the engine, thus far this has not worked.

The only other suggestion I have been told is to remove the upper rubber mounts on the saddle assy and then drill a 1" hole in the leg so I can a hacksaw blade in there and saw the shaft off, repair the hole after everthing else fixed (water pump)

Has anybody done this before or have any other ideas on how to get this apart without sawing the shaft off??

Any Help would be great.

Steve Anstey

The way I do this sort of thing is to make an adapter for the crankshaft thread.---------------------drill a hole in the skeg in the correct spot.-------------Attach a chain to the skeg with a bolt.--------Anchor the motor to something solid and use a puller on the chain to pull it apart.--------This cutting of the driveshaft seems rather drastic and expensive !

Another method is to run the motor and shake it loose. The trick there is to rope the LU to the tower so it can't fall all the way off.

Jeff

PS: I'm afraid you'll find that the driveshaft and/ or crank splines are shot when you do get it off.

racerone said:

The way I do this sort of thing is to make an adapter for the crankshaft thread.---------------------drill a hole in the skeg in the correct spot.-------------Attach a chain to the skeg with a bolt.--------Anchor the motor to something solid and use a puller on the chain to pull it apart.--------This cutting of the driveshaft seems rather drastic and expensive !

Click to expand...

I am not sure what you mean by making an adaptor for the crankshaft thread, I can't to the crankshaft???

But drilling a hole in the skeg is something I never thought of, right now I have a heavy duty strap that you use for towing cars wrapped around the lower unit (i will post picture) I can use that to pull on the lower unit......

Where do you drill the hole in the skeg, how big, and is there a danger of breaking the skeg off? The metal in these engines is about as strong as a bar of soap


Thanks will try that.

That sounds like it may work, but a few questions.....

Just run at idle? shift gears? rev the engine?

Thanks,

Steve

racerone said:

The way I do this sort of thing is to make an adapter for the crankshaft thread.---------------------drill a hole in the skeg in the correct spot.-------------Attach a chain to the skeg with a bolt.--------Anchor the motor to something solid and use a puller on the chain to pull it apart.--------This cutting of the driveshaft seems rather drastic and expensive !

Click to expand...

see attached pics

You remove recoil starter and remove flywheel nut.--------Screw on an adapter so you can anchor that powerhead firmly to something -----A wall / a tree / a truck . concrete floor etc , etc

Ok got ya now, good idea.....

Not really. Something's bound to get wrecked doing it that way.

Jeff

Ok I have had the engine hung upside down for days now, and have been spraying penatrating oil down the shaft and also heating the shaft thru a hole I drilled thru the leg. Also anchored the engine to the floor and have alot of pressure applied via a come-along....the lower unit has not moved a bit.

Anybody got any other suggestions???


I am soon going to resort to the hacksaw......

I told you how to get it off.

Jeff

OK, I will try running the engine and shaking the lower unit off.....do you suggest shifting in and out of fwd/rev????

thanks

Steve