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

The pump kit in post 49 retains the stock rear plate with the air drain, The pump in post 50 is a standard bravo back half. I have bought both for different engines though. Randy

the gen 7 496 hardin pump is different than the standard bravo, they run around 400, but use a standard impellar opposed to the factory 496 brass pump

I want this pump as a spare , I have a new pump. I have machines it to 2.000 of depth bu if any knows the OEM spec depth it would be appreciated , thanks

Check the little air fittings that go to the air actuator. I had a small leak in mine which allowed air to leak and cause the pump to cavitate

I've used Aftermarket Marine's IM496REB rebuild kits over the last three years. They continue to improve the product offering and when presented with a problem on a rebuild with two years of service on it they sent me out a new kit on their dime :ernaehrung004:. The Youtube video below shows how this kit is installed, what the damaged pump looks like and how the stainless end plates fair after two seasons of use.

https://www.youtube.com/watch?v=oqnV-FJhRvg

Okay, my 04 sunsation with 496 h.o. is 12 years old, took it out for the first time this season, coming off plane temp spiked to 180 and alarm went off. turns out the serpentine belt was loose and slipping, ordered a new belt, but an thinking this would be a good time to address the impeller and is probably well beyond needing replacement.

which kit would be my best bet,,,, i'm thinking the im496reb kit Nauti posted ???

I rebuilt mine with the im496reb kit this winter. Nice kit. Visibly pumps more water out the tips vs worn stock housing. Plan on hooking up the scan tool this weekend to see water psi numbers.

they sell alot cheap china junk just saying and their feedback is poor, just do small search up here s some OSO mems had problems with them

here read on and they have a very unorganized shop as I heard about 100 times.

http://www.offshoreonly.com/forums/b...arket-com.html

I've dealt with them several times over the last (3) years and even when I had a problem with an early revision of the impeller they made it right a year after the original purchase. I'm two seasons into these latest revision impellers and no issues. Hardin makes some top notch stuff, but have had a problem with their pumps as well. Both stepped up and made it right, but biggest difference was Harden is a retailer and selling products is their primary business.