Hi there,
I just thought I would share with those do it yourselfers what I did in order to get my seized shift shaft bushing out of a 1980 merc 115 2 stroke inline 6.
After doing a pressure test I noticed the bushing was leaking and I wanted to get the boat on the water but wasn't taking it out with water in the gear case.
Local boat shop was closed for the weekend and the job had to be done.
After using a chisel and hammer, as well as a variety of other unsuccessful tools and objects, I decided to make something for the job.
Total cost of the job: under $10
Tools and supplies needed:
-Bench Grinder with coarse grit stone
-24" piece of 3/4" gas pipe --> you can get this at most supply stores.
-A little bit of time and a drink
So lets get started.
The bushing to be extracted looks like this and is located near the drive shaft inside the lower end:
The bushing has two notches located on either side but the tool also needs to slide over top of the shift shaft.
Step 1:
Begin by taking the 3/4" piece of pipe and start grinding down one third of the pipe.
you want to leave enough room to have a notch in the center the size of the notch in the bushing.
Remember you can always take more off the center but you cant add to it without starting over.
Also if your bushing is really seized you may need to cut the threads off the pipe before beginning this will make the tool stronger.
Grind this down until you are into the pipe about a half inch.
Step 2:
After grinding down the first side of the pipe do the same thing to the other side.
Don't forget to leave enough steel in the center as stated above.
Step 3:
Now you have ground down both sides to a depth of 1/2 inch (roughly) you will be left with a small extrusion of steel on either side of the pipe. Carefully grind these extrusions on either side until they fit snug on the bushing.
Use your replacement bushing to test the fit
You want to make sure it fits perfectly flat against the bushing and also fits snug in both notches.
(shown below)
Be sure to keep the edges on the extrusions as square as possible. This will stop the tool from slipping.
Step 4:
Now your tool fits into the bushing properly lets begin grinding it down a little bit.
The diameter of the particular pipe I used was a little bit too thick to fit down snug on the bushing, So I took my bench grinder and began spinning it on the grinding stone until I took about 1/16th of an inch off the pipe all the way around. This only needed to be done from the bottom of the pipe up 2 inches.(This may be different on other motors) ---> until it looks like this photo.
Now(on my particular engine) - There is enough room for it to slide down over the shift shaft and lock into the bushing without any resistance from the sides of the lower unit.
Step 5:
Now we want to make 2 holes in the top end of the tool.
In my case I just used the grinder to make 2 rectangular holes in the pipe about 1/4 of the way through.
These will allow us to put a bar through the tool and get some leverage on it
Notching it with the grinder will take some time but it gives the perfect size holes when finished.
Do this to both sides of the tool until you have something like this.
We now have enough room to put a bar through the top of the tool.
Step 6:
**Typically if the bushing needs to be replaced it is going to have a bunch of junk down in the notches. I used a small flat head screw driver to clean them out**
Find a bar that will fit through the hole, In my case I just used a socket extension. But anything strong should do the trick.
Place the tool down over the shift shaft and lock it into the bushing.
Put your leverage bar through the holes we made and use it to turn the bushing loose keep your body weight on the tool to help keep it down tight.
**Again be very careful not to damage the shift shaft or the drive shaft while doing any of these steps**
VERY Important:
Only use the tool to get the bushing loose,
Once it is easily turned by hand remove the tool, HOLD THE SHIFT SHAFT DOWN WITH YOUR HAND AT ALL TIMES WHILE REMOVING THE BUSHING.
YOU DO NOT WANT IT TO POP OUT OF PLACE.
Out with the old and in with the new.
Congratulations, you now have a tool that you can keep and use anytime you need to change this bushing.
Just a few notes:
-I am by far not a mechanic
-I'm sure there are many better ways to do this, I just wanted to post how I did it in hopes that it might help someone else who needs to do the job
but are unable to purchase the actual tool, Due to holidays, Hours of operation etc etc
-If you would like to improve on this design, Please feel free.
-I have no idea which other engines this will work on
- I tried to be as detailed as possible through the entire process to eliminate any confusion.
Regards and happy boating
Justyn Rook
Rooky5000
