identifying part number for water pump rebuild

[hotrod53]

OK, so I took out the water pump and here is what I found:

Impeller has a .75" center hole
height is .72"
diameter is 1.76"
it has two gaskets and 1 metal plate under the impeller, 1 O ring where the water tube goes and one large ring that goes over the shaft.

The casting number is #1643-6458 and it is a 1977 blue band 500 4 cylinder.

Just not sure what or where to order from.

 

[Chris1956]

Re: identifying part number for water pump rebuild

Gee, Order a waterpump repair kit for a '77 Merc 500.

 

[hotrod53]

Re: identifying part number for water pump rebuild

LOL... if it were only that easy...

The lower unit on this motor is being replaced, the casting number that I gave is not the original to this motor. Maybe they are all the same, maybe not...thus my question..

This is my first build and I have a few questions, please bear with the nube questions.

Original lower unit casting number #1643-6037
replacement cast number #1643-6458... what its off of I don't know.

 

[SigSaurP229]

Re: identifying part number for water pump rebuild

It should be exactly the same maybe a little newer but Mercury used the same water pump for many years.
As for where to buy one try

www.iboats.com

 

[sxmerc]

Re: identifying part number for water pump rebuild

Not sitting in front of the EPC right now, but I believe what you need is part #46-77177A3

 

[hotrod53]

Re: identifying part number for water pump rebuild

I searched for that number and it says 50HP(4 cyl) S/N 4965056 & UP. my serial number is #4803973 but my lower unit is not original, it's casting #1643-6458 instead of the original #1643-6037

 

[Fun Times]

Re: identifying part number for water pump rebuild

I guess I had some useless information, But at least it called out someone with experience like below.

 

[Laddies]

Re: identifying part number for water pump rebuild

A word of advice, when asking for help listen to a mechanic (like Chris) that is speaking from experince not a computer geek thats passing links around and reading to you from a manual. All water pumps for the 500-50-45 and 45 and 40 HP 4 cyl engines built from 1961 to 1996 use the same upper water pump kit, which will repair the pump however if you need the water pump base then there are 3 kits 46-77516A3 the base has a threaded flush plug hole serial #2514919 to 4357639 the second has a pump base with a unthreaded hole for flushing #4357640 to 4962055 and the newest has no flushing hole drilled in it #4962056 and up. How hard is that!

 

[hotrod53]

Re: identifying part number for water pump rebuild

OK, sounds like it should be easy, ask for an upper kit and they're all the same. I did pull the old pump and the new pump and compared them, they are the same from what I can tell.

The lower unit that I bought has no impeller cup or impeller, we wanted to be 100% sure that it got replaced. The body looks good and the tops, eventhough they are shaped slightly different and made of 2 different materials, look internally the same.

I found a number on the new pump top 46-7782 if that means anything.

Does the impeller cup just press out?