Correct, the first twenty shaft were undercut and sold with a $20 discount.

a Youtube video on the install would be a great idea, I still have the stock water pump, I just changed the impeller last year, I am new to boating and the 496 and made the mistake of trying the air pump system without knowing about how it really worked, I started the motor before releasing the pressure from the pump system so im wondering if i damaged the impeller. Im sure it cant hurt to change the impeller for routine maintenance anyway, the only thing that sucks is that I dont have a whole lot of room to get to it (Checkmate Convincor 270 + 6'1" at 255 lbs = not a lot of room) I had my local marina change it for me last year and they took the back seat out and charged me $300 just for that, I enjoy doing my own work, and take pride in it, but I need to learn more, I love Youtube videos, especially in the winter, they give me something to do during the winter months and I love to learn as much as I can.

We're a little backed up in the shop at the moment, but I think we can have you a video by the end of the week. We currently have a Baja in the shop thats getting some work done and needs one of our kits, so it should not be a problem. Once I get it up on youtube, I will post it up on here.

For now, here is a video of the test we did on the pump back in June of 2011.
[YOUTUBE]http://www.youtube.com/watch?v=Ks-SwVgu90o&feature=results_video[/YOUTUBE]

It's easy. Loosen the serpentine belt. Be careful prying the hoses off so you don't break the plastic housing. Remove the bolts holding the plastic housing on. An assortment of wrenches is helpful. Take the housing indoors. I like to warm up the new impeller with hot tap water first then use anti-freeze or vasoline as lubricant to install it. Make sure the vanes are bent the same direction as the old one. Do it every spring. I have the Hardin Marine SS housing but the procedure is the same.

Its in storage right now, but for the few bucks it takes to change it, I would like to just for a little added insurance, I would rather spend a couple hours and a few bucks at the beginning of the year then to be towed off the lake, Im just hoping I can get to it, like I said there is not a whole lot of room for me to fit in there.

Seawater pump 496 mercruiser machining
 

Hello, I am new to the form . Does anyone know what the mercruiser OEM depth is on the seawater pump housing. I am a machinist and intend to machine the bottom of the housing bore to remove the grooves and them remove the appropriate material off the face . I appear the original dimension was 1.997" . Does anyone have a new pump housing to
Measure or know the mercruiser spec . Thanks

I have not read every post in this thread about the pump. Here's the deal throw the Merc away; buy one from Hardin Marine with pulley about $500 It is rebuild- able, I have used a few of them.

I concur! :)
http://i763.photobucket.com/albums/x...s144Medium.jpg

This is the one I was referring to.

http://www.hardin-marine.com/p-16817...th-pulley.aspx

I think this one fits the 496 also and is only $190 list. I think I bought mine from CP Performanve. Either way, the plastic has to go!

http://www.hardin-marine.com/p-14544...rhaul-kit.aspx