Dropping the foot

Rum_Pirate

Rum_Pirate

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85hp Yamaha 2 stroke outboard, actually two of them.

Want to drop the foot to change the water pump impeller.

All bolts, including the one for the trim tap, have been removed.

The foot will not drop.

Seems that the shaft has

- the grease congealed into a glue or

- the foot shaft will have corroded on to the drive shaft or

- both !!!!
​

Please post suggestions in how to best (and inexpensively) way to free it and drop the foot.
 
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I seem to recall putting a piece of wood on each side of the cavitation plate and tapping the wood with a mallet or hammer.
Disclaimer, I accept no liability with this advice:p
 
You gotta do this every 3 yrs or they seize, even if the pump doesn't need work. On all saltwater outboards. IMHO
The shaft splines seize, but most of all the dowels (ss dowels into an ali casting, erk) seize.
You have to hit it hard with a mallet, which isn't easy.
If no good you need heat (hot air gun) on the dowel areas (see picture above) - fortunately for you the coefficient of thermal expansion of ali is about 1.5x that of stainless steel.
Once you get 1-2mm of gap, you can use wedges and it is plain sailing
 
jfm said:
You gotta do this every 3 yrs or they seize, even if the pump doesn't need work. On all saltwater outboards. IMHO
The shaft splines seize, but most of all the dowels (ss dowels into an ali casting, erk) seize.
You have to hit it hard with a mallet, which isn't easy.
If no good you need heat (hot air gun) on the dowel areas (see picture above) - fortunately for you the coefficient of thermal expansion of ali is about 1.5x that of stainless steel.
Once you get 1-2mm of gap, you can use wedges and it is plain sailing
Click to expand...

Where in picture (in Post #3?) ?
 
When my old Merc 50 got stuck like this my local marine mech's helped me by roping a plank across the anti vent plate and then the two fattest guys there jumped up and down on it in unison.

There was a hell of a bang when it came free! :)
 
I've seen gearboxes stuck on so hard you'd think the crank and driveshaft were welded together. Many years ago we stripped an engine so far that all we had left was the crank and shaft & had still had to use heat to part them. By all means attempt to get it apart, & if its just the little dowels then your laughing but if its the shaft to crank you may find you destroy something trying to part the pair. You will need to decide at some point wether your going to wreck something to part it or give in and run the engines until the impellers eventually dies and you have nothing to loose by being brutal with it.
Its an old engine so eeking out another two or 3 seasons might be the best option.
 
Beamishken said:
I've seen gearboxes stuck on so hard you'd think the crank and driveshaft were welded together. Many years ago we stripped an engine so far that all we had left was the crank and shaft & had still had to use heat to part them. By all means attempt to get it apart, & if its just the little dowels then your laughing but if its the shaft to crank you may find you destroy something trying to part the pair. You will need to decide at some point wether your going to wreck something to part it or give in and run the engines until the impellers eventually dies and you have nothing to loose by being brutal with it.
Its an old engine so eeking out another two or 3 seasons might be the best option.
Click to expand...

I have watched this Video with some trepidation.

Previous technician didnt grease the splines on the driveshaft, gearcase was not removed in 4 years.
Click to expand...

Have to initiate the movement with an old kitchen knife to get space for larger wedges!!!!! :ambivalence: :ambivalence: :ambivalence:


Once it moves bit, may be able to spray some 50% acetone/50% Automatic transmission fluid up onto the splines.

Further suggestions welcome.
 
Masters of understatement

https://www.boatus.com/magazine/2017/february/outboard-water-pump-service.asp

3. Loosen and remove the nuts that hold the lower unit in place.
Almost every outboard has four nuts holding it.
A socket may not fit, so use a ring wrench to give good purchase on the nuts, which probably will be difficult to loosen.

Using rubber mallet to free lower unit

4. Theoretically, the lower unit should now be free; in practice, it invariably sticks and will need a few taps with a soft mallet.
Do not hit the flange cavitation plates at the sides or they're sure to break.
A few taps on the aft end of the gearbox unit, as shown here, is acceptable.
Click to expand...
 
"Almost every outboard has four nuts holding it."
Nope, nearly always an odd number - 5 or 7. There is invariably a nut aft, hidden by the anode tab
 
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