1961 Merc 400 - Changing impeller

[lindy46]

Looks like a special tool is needed to get to the water pump impeller. Can this cover be removed in any other way? I've looked on Ebay for the tool and have had no luck. Anyone know where to find one? Also looks like a similar tool is needed to remove the prop shaft cover. Are they the same tool?

 

[coolguy147]

Re: 1961 Merc 400 - Changing impeller

ya there is but it might damage the water pump cover beyond use. i ahve a 1961 mercury 500. baseically almost same thing as yours. i used the good size punch. then punched some hard ones. try to aim the punch toward the inside and down nice and snug so it wont slip. if you aim outwards it will break. but think about it aim where it will give you good leverage. try some wd-40 and sit? then as it gets looser use light punches just enough to move it around.

or you could use a spanner wrench

 

[emckelvy]

Re: 1961 Merc 400 - Changing impeller

What you're looking for is on Page 4 of this list of old Merc special tools:

http://www.pfs-ware.com/WhitePapers/pdf/MercTools.pdf

"C-91-22119 - GEAR CASE & WATER PUMP COVER TOOL
Removes and installs gear housing cover, all
models except Merc 650 and late Merc 500 models
A-17-25104 Replacement Pin"

These tools typically have (2) or (4) pins in the face to engage the cover holes, and are set up to handle one cover on one side of the tool, flip it over to do the other cover.

Hard to find as you've discovered. Armed with the part number, you might have a better chance of rounding one up.

You might also have luck with an adjustable face pin spanner wrench such as this:

http://www.google.com/products/cata...ct=result&resnum=1&ved=0CA4Q8wIwAA#ps-sellers

A google search will produce many results and I expect you'll find quite a few on eBay as well.

You do have to be careful when using this type of wrench because it's easy to slip out of the holes and mess them up.

If the motor's been fresh-water run all its life, the cover will probably spin out without too much drama. Salty Dogs will have their covers 'welded' in to the point where you may not be able to get them out, no matter how much heat applied or penetrating fluid. In that case, you may have to sacrifice the cover to get things apart. You can drill it to weaken then crack with a small chisel.

These guys have replacement parts:

http://www.eastcoastmarineservice.com/lowerunit.html

HTH & G'luck with the impeller replace..........ed

 

[coolguy147]

Re: 1961 Merc 400 - Changing impeller

i had to use a punch on mine because it was already tampered with if yours isnt i say go for getting the right tool

 

[lindy46]

Re: 1961 Merc 400 - Changing impeller

Still looking for the tool. If I could find one, I'd buy it, but no luck so far. Wow- these things sure are more of a hassle to work on than the Johnnyrudes.

 

[coolguy147]

Re: 1961 Merc 400 - Changing impeller

Still looking for the tool. If I could find one, I'd buy it, but no luck so far. Wow- these things sure are more of a hassle to work on than the Johnnyrudes.

whats harder is trying to get the impeller out then and the new one in.

dont lose the key!!!

i had to drill mine out.

 

[Chinewalker]

Re: 1961 Merc 400 - Changing impeller

If you use a punch of approximately the same diameter as the holes in the cap, hold the punch parallel to the driveshaft. Using a long, heavy screwdriver, use the driveshaft as a fulcrum with the tip of the blade behind the punch. Sometimes you may have to use CoolGuy's method to break it loose, but once loose, use the lever method to remove it the rest of the way - might save the cap. If the cap does bite it, they are being repopped and are available at oldmercs.com.

 

[coolguy147]

Re: 1961 Merc 400 - Changing impeller

like i said once its lose your good to go.

im telling it really is harder to get the impeller in and out then getting the cap off

 

[lindy46]

Re: 1961 Merc 400 - Changing impeller

Since I've got until April before she goes back in the water, I'll continue looking for the proper tool to do the job right. I hate to mess anything up, since the motor is pristine and seen little use. Thanks for all your suggestions.