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496 raw water pump problems
I have a 496 Mag with a Bravo drive. I had the impeller in the raw water pum changed now everytime I put the boat in the water I have problems getting the pump to prime unless I take off wide open as soon as I start the engine. After the pump takes prime its fine til I pull the boat out of the water then its the same thing again.
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It seems that too many Merc 496 owners have problems after impeller change outs and the problem 90% or more of the time is from just replacing the impeller only on the pump without dealing with the grooving that can and does appear on both inside and plate end of the pumps. these groove is anything other that very slight in depth and quantity will cause the impeller not to seal properly at the ends and hence not be able to properly prime at start up and provide enough water pressure over the entire rpm band to keep the engine cool. There are now a few kits available that install stainless end plates in the worn housings with a special replacement impeller to correct this grooving problem. The only other items that can sometimes make priming difficult are, air leak on intake side of the hose, crimped small hose that comes thru Bravo drive at transom plate, or debris in intake or same Bravo transom water pass thru point.
link to water pump kit: www.jcmarinellc.com Don't just plop in impellers without inspecting and making necessary repairs to the pump housing or replace the housing entirely. Best Regards, Ray @ Raylar |
Agree completely!
I just put a new impeller in my 496mag ho brass housing and yes, I too have those scratches inside the housing (I knew it when I put in the new impeller-original housing, now 10 years old-not too shabby for brass and constant sand!). No problem priming but it seems like I too am dumping less water and the boat is running a little warmer than normal (running at 175 when running and can get up to about 185-188 it seems when coming back down on plane). I am going to either purchase a new housing or get the kit. I heard Captains CHoice in Ft Walton was working on a kit with same design per say but a slightly smaller impeller that would not require any modification to the factory bracket or silicone and such. I am going to wait a few weeks and then change.
Link to the kit (if still available): http://www.randrproductslakehavasu.c...pump_kits.html |
rebuild kits
Originally Posted by Raylar
(Post 3415628)
link to water pump kit: www.jcmarinellc.com
Don't just plop in impellers without inspecting and making necessary repairs to the pump housing or replace the housing entirely. Best Regards, Ray @ Raylar I installed two of these kits (from JC Marine) in my 496's just yesterday. My originals were 8 years old! After re-installing the pumps, I backflushed and then pre-filled the raw sea water system. Did 70 miles on Lake Huron today. No problems at all. Good flow out of my exhaust tips, and steady engine temps of 160F. |
Originally Posted by TWP1972
(Post 3415417)
I have a 496 Mag with a Bravo drive. I had the impeller in the raw water pump changed now every time I put the boat in the water I have problems getting the pump to prime unless I take off wide open as soon as I start the engine. After the pump takes prime its fine til I pull the boat out of the water then its the same thing again.
If you're not that guy and you just want to buy these features incorporated into a new polished stainless steel housing then here's another option. http://www.hardin-marine.com/p-15774...d-502-mag.aspx |
The other thing I see a lot of problems with is with the freshwater flush setups that some manufacturers install. Bottomline: The ones with the check-ball/spring system SUCK! They just get clogged up with sand/seaweed, and other crap, especially if you don't have sea strainers.
You don't need the check valve T-fitting in there, period. You just need a plane old T-fitting. You turn on the water hose, and it flushes from the T-fitting out the drive. Then start the engine, and water will be sucked into the impeller. It's that easy. A friend on his brand new Baja had his get all gunked up, and another friend has what I believe to be the same problem on his 29 Outlaw as of yesterday. All of the above is correct too. If the pump is even slightly scored, it's junk. The pumps are only about $100. IMHO, if you are preventative maintenance replacing impellers, just do the impeller and O-ring. Howerver, if you are recovering from impeller failure, replace the whole pump. |
I just put in the kits from JC Marine and my historically crappy water pressure improved 100%. Pressures improved at idle and at speed. Engine temps no longer spike when coming off plane either.
Now, if there is evidence that this is a temp fix I will have to keep an eye on it. I'm just glad for the first time in many boating seasons I am starting out with good pressure on both motors. Question for the Hardin Marine folks. Does that stainless steel replacement pump incorporate the quick drain valves of the factory unit? From the picture I don't see the dump valve? |
Originally Posted by techman
(Post 3416528)
I just put in the kits from JC Marine and my historically crappy water pressure improved 100%. Pressures improved at idle and at speed. Engine temps no longer spike when coming off plane either.
Now, if there is evidence that this is a temp fix I will have to keep an eye on it. I'm just glad for the first time in many boating seasons I am starting out with good pressure on both motors. Question for the Hardin Marine folks. Does that stainless steel replacement pump incorporate the quick drain valves of the factory unit? From the picture I don't see the dump valve? I also had someone call today questions the mounting positions. Our pumps were designed from a clean slate so that when the wear plates were incorporated the mounting positions would be in there original location. We also chose to use the common mercury impeller that has been in every pump for the last 20 years. The original impellers use a larger stronger shaft. But the main reason was if you were in the middle of no where and needed a impeller you more than likely could find it since it is so common as the 496 impeller is tough to find in many places. Other than that it's just better materials and the incorporated wear plates that allow the pump to have a much longer service life. Happy Boating |
If your pump requires the re-use of the original rear housing how does that address the potential scoring on that side? It would seem that your pump only addresses half (roughly) of the problem of the scored pumps.
My OEM pump had scoring in the main housing and the back plate. And the shim kits cover both sides. Am I missing something? |
it has a new rear wear plate and a gasket that goes inbetween the old rear plate and new wear plate....i just bought one a few weeks ago and it works great with no modification whatsoever
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Got it!
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Hardin:
Your new Mercruiser late model stainless steel water pump looks like a nice piece and a welcomed addition to the mercruiser grooved bronze pump. I just have a couple of questions, does it have a plate insert or new rear cover as the grooving that occurs on the stock brass plate is one of the pressure and pumping losses that occurs on the stock pump. Is this pump configured to bolt directly back into the stock mercruiser bracket and accept the stock pulley, I assume it is but just clarifying. Good Job on a needed new product! Best Regards, Ray @ Raylar |
Originally Posted by Raylar
(Post 3417392)
Hardin:
Your new Mercruiser late model stainless steel water pump looks like a nice piece and a welcomed addition to the mercruiser grooved bronze pump. I just have a couple of questions, does it have a plate insert or new rear cover as the grooving that occurs on the stock brass plate is one of the pressure and pumping losses that occurs on the stock pump. Is this pump configured to bolt directly back into the stock mercruiser bracket and accept the stock pulley, I assume it is but just clarifying. Good Job on a needed new product! Best Regards, Ray @ Raylar The pump uses an internal wear plate as well as a wear plate between the rear housing and cover so basically on each side of the impeller. All of these dimensions were factored into the design of the pump so that the original bracketry will work. It comes with the gasket for re-assembly to the OEM rear cover Thanks on the accolades it really is a great pump I think you will hear a lot more positive press. Sincerely |
Originally Posted by techman
(Post 3416818)
If your pump requires the re-use of the original rear housing how does that address the potential scoring on that side? It would seem that your pump only addresses half (roughly) of the problem of the scored pumps.
My OEM pump had scoring in the main housing and the back plate. And the shim kits cover both sides. Am I missing something? Nothing is wrong with the repair kits sold. If you know EXACTLY what your wear tolerances are and or can machine all of your bronze parts to those spec's and then again modify your mounting bracket they will work fine as well. |
Excellent clarification!
OK, so I was one of those pathetic sheep following the herd, and I just plunked in the new wear plates, new impeller, gaskets and machined down my bracket so it would all fit. I did nothing in terms of figuring out what my actual wear tolerances were. To me, it seemed that the new impeller is now riding against two new smooth ends and more or less fixed the pumping problem caused by the soft brass wear and tear. What exactly are the "real world" experiences when just doing what I did? Will the impeller wear be in question because of the housing variances? To me, I covered over grooves in the housing and back plate that were creating the seal problem. Those grooves I would imagine would have to be measured with a micrometer. Are tolerances really that small in these pumps? Raylar Ray, you need to set up a "tech corner" on your website. Seems like with all the traffic you get with 496 questions you could easily start one that would help increase traffic to you product web site! Cover all the common issues, like Pumps, Headers, air filters versus stock spark arrester, common part #'s to name a few! I bet once you did if anyone should ever Google "496" your site would be top hit!!! Just a thought! |
Hardin Marine Impeller Housing-Kit
Just got my new stainless steel kit referenced above and it went in PERFECTLY!!!!!!!!!!!! No mods, no drilling, swapped pulleys over in minutes with a puller and press, dumps a TON of water!!!!! No rebuild kits for me !
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I put a Hardin SS water pump housing on my 525. IDK why the hell a "racing" engine comes with a plastic raw water pump. The Hardin piece is a wise investment and priced reasonably.
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Hardin:
Is the pump available with a pulley installed? It is a pain to R&R the pulley, so I would like to purchase the stainless version with it attached and keep the original as a back-up. Also, the companion end plate, is it threaded for hose fitting requiring additional purchases? |
So from what your saying it appears your new pump will back fit all the way back to the old style Mercruiser two piece plastic body style impeller housing that used the two stainless steel ware plates and related gaskets? Also it appears it will fit in place of the newer one piece plastic body housing Mercruiser came out with in 1996? Correct? Also it appears your new pump will fit in place of the newer brass style housing all this while using the old style Rubber impeller, Mercruiser part number 47-59362T1.
Also just so that it's clear, the rubber impeller that fits inside the newer brass style Mercruiser housing, Mercruiser part number 47-862232A2 will not fit inside your new pump housing. Correct? http://www.mercruiserparts.com/bulle...1996/EN_08.PDF I just wanted to say, If so Good Job, even if it will not fit all three, still you guys did a good job with the new housing. congratulations :coolcowboy:
Originally Posted by Hardin Marine
(Post 3416651)
Our pump accepts any of the seven different back housings they bolt to our unit just like the factory unit. So to answer your questions you retain that part from your original assembly.
I also had someone call today questions the mounting positions. Our pumps were designed from a clean slate so that when the wear plates were incorporated the mounting positions would be in there original location. We also chose to use the common mercury impeller that has been in every pump for the last 20 years. The original impellers use a larger stronger shaft. But the main reason was if you were in the middle of no where and needed a impeller you more than likely could find it since it is so common as the 496 impeller is tough to find in many places. Other than that it's just better materials and the incorporated wear plates that allow the pump to have a much longer service life. Happy Boating Just about everytime a new impeller was needed it was time to change the stainless steel ware plates due to deep grooves/gouges from either sand or the impeller itself. obviously Mercruise knew of it back then, They sold an impeller kit that came with the stainless steel ware plates that needed to be changed out as well about every 100 hours or so of use.
Originally Posted by Hardin Marine
(Post 3416337)
I think you should investigate the repair kits in depth and ask the dealers that have installed them for some real world reviews.The whole reason we designed our new pump was we heard endless complaints about the fact that due to varying pump wear these plates could not always bring the pump back to its original performance. They would work initially just to fail prematurely.
But if your wear is in excess of the new plates then you cannot get the pump back to a OEM spec. I'm not saying the kits are bad it's just that providing two wear plates and an impeller for a pump with unknown wear will never fix all applications. Impeller crush or end clearance is what determines how well your pump performs.
Originally Posted by Hardin Marine
(Post 3417442)
Maybe your not missing anything I probably wasn't clear. The pump uses a stainless steel wear plate between the body and the rear cover as well as the front housing. The impeller rides against all fresh smooth surface's. and the impeller has factory OEM load spec's. This merely a new pump with wear plates designed into it from the beginning and manufactured from stainless steel.
Your new pump housing goes past just the High performance crowd, You will have the sea rays, Bayliners, cobalt style boats wanting in on the action as well.:) I hope it goes well for you, Good luck with it.:) |
As a better selling feature you should consider doing/posting a complete step by step write up on all the boating forums you participate in on how to install your new style impeller pump housing from start to finish while working inside a boat with detailed photos attached. Also you should consider doing a youtube video to help demonstrate the actual key points of the demonstration, Then post the link with the write up on the forums. This same write up idea would be good for all the boating Magazines that are still left out there as well.
Your new pump housing goes past just the High performance crowd, You will have the sea rays, Bayliners, cobalt style boats wanting in on the action as well. I hope it goes well for you, Good luck with it. This would be an awesome episode of ship shape TV. Instead of the latest and greatest mold cleaner how about the latest and greatest water pump that will stop mercury from mugging us every time we need to service a water pump Chris |
Originally Posted by Blueabyss
(Post 3426321)
As a better selling feature you should consider doing/posting a complete step by step write up on all the boating forums you participate in on how to install your new style impeller pump housing from start to finish while working inside a boat with detailed photos attached. Also you should consider doing a youtube video to help demonstrate the actual key points of the demonstration, Then post the link with the write up on the forums. This same write up idea would be good for all the boating Magazines that are still left out there as well.
Your new pump housing goes past just the High performance crowd, You will have the sea rays, Bayliners, cobalt style boats wanting in on the action as well. I hope it goes well for you, Good luck with it. This would be an awesome episode of ship shape TV. Instead of the latest and greatest mold cleaner how about the latest and greatest water pump that will stop mercury from mugging us every time we need to service a water pump Chris Best Regards |
Originally Posted by lakematdude
(Post 3425942)
So from what your saying it appears your new pump will back fit all the way back to the old style Mercruiser two piece plastic body style impeller housing that used the two stainless steel ware plates and related gaskets? Also it appears it will fit in place of the newer one piece plastic body housing Mercruiser came out with in 1996? Correct? Also it appears your new pump will fit in place of the newer brass style housing all this while using the old style Rubber impeller, Mercruiser part number 47-59362T1.
Also just so that it's clear, the rubber impeller that fits inside the newer brass style Mercruiser housing, Mercruiser part number 47-862232A2 will not fit inside your new pump housing. Correct? http://www.mercruiserparts.com/bulle...1996/EN_08.PDF I just wanted to say, If so Good Job, even if it will not fit all three, still you guys did a good job with the new housing. congratulations :coolcowboy: As I'm sure all those other repair kits with the stainless steel ware plates are going to work good. I'm going to venture to say i wonder how long they are going to last. I say that because if everyone would think back to the two piece impeller body housing Mercruiser first started using, (See service bulletin Above) We have already went through the real world experience with using stainless steel ware plates.The plates didn't last all that long themselves. Just about everytime a new impeller was needed it was time to change the stainless steel ware plates due to deep grooves/gouges from either sand or the impeller itself. obviously Mercruise knew of it back then, They sold an impeller kit that came with the stainless steel ware plates that needed to be changed out as well about every 100 hours or so of use. I am a little curious though, would you be able to elaborate yet on how much testing you have done and how your new pump appears to be holding up thus far? If not, I'll understand.:) Thanks. As a better selling feature you should consider doing/posting a complete step by step write up on all the boating forums you participate in on how to install your new style impeller pump housing from start to finish while working inside a boat with detailed photos attached. Also you should consider doing a youtube video to help demonstrate the actual key points of the demonstration, Then post the link with the write up on the forums. This same write up idea would be good for all the boating Magazines that are still left out there as well. Your new pump housing goes past just the High performance crowd, You will have the sea rays, Bayliners, cobalt style boats wanting in on the action as well.:) I hope it goes well for you, Good luck with it.:) As for the repair kit your correct that's the whole idea is for the wear plate to wear out with the impeller and not the housing. That way you can service our new pumps down the road for only $69 for new plates, impeller, and gaskets as apposed to a $350-$500 pump assembly. As for duration of time in the field the GEN 7 pump has only been in the field for less than a year as it is a new product for us. Keep in mind we have been building pumps for over 30 years this is not a new project to us. When Mercury made the new pump we didn't expect it to be so poorly reliable. But now we have witnessed a concerted effort by Mercury to build products that will need replaced. Their not interested in products that last a life time. We knew we could build a superior part. Thanks for the many accolades we are in development of so many new products the future is VERY exciting....Best Regards |
Where can I get one and how much and how soon can you get it to me?
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So i have already machined down my bracket for the other kit but am not totally satisfied. I quess i will need a new mounting bracket to in stall the hardin pump ?.
Looks like a great solution , Thanks |
I am tired of the fluctuating cooling temps and leaks from the 496 factory pumps. Got a special deal for someone needing three pumps? I am ready to purchase!
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Originally Posted by kr1276
(Post 3666453)
I am tired of the fluctuating cooling temps and leaks from the 496 factory pumps. Got a special deal for someone needing three pumps? I am ready to purchase!
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Kr1276 , We and many of our 496 customers have now used the Hardin stainless replacement pump with great results and sucess. Its a wonderful replacment part, far better than the original merc pump.
By the way, they do have a great deal on three pumps, they have them in stock and thats the great deal cause if you wait they will be out of stock and on back order as more 496 owners start using them! Be smart order now! Best Regards, Ray @ Raylar |
Assembled my new Hardin pump yesterday. It looks like top quality unit and assembly was straightforward. Will try it in the water this weekend.
The only difficulty for me was the pulley. The original pulley center lip snapped off last week when trying to use a puller to remove it. Had to order a new one. $75 and 3 days. It took a lot of work and cuss words to install the new one even with an installation tool. I wsh there was a better system for that part. |
A Powerbuilt powr steering/Alt puller kit works easily to pull and install. Kit 20 part #648605. I bought the Hardin pump to carry on the boat and had a extra pulley so I can change it on water if needed. Nothing worse then havoing to get towed in because of a raw water pump failure. Haven't needed it yet and it is a great alternative to having to by the Merc Housing every time at their inflated price.
(if changing out on the water just be sure to have a D sized battery or something capable of pluging the inlet hose) |
Hardin pump worked great. 2.7 PSI at idle (up from 2.1) right from the start. No leaks and it looks good as well. Nice product.
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I toasted my impellor and my housing has lots of scratches. I installed a new impellor but cannot get the pump to flow enough water.
I'm looking to replace my pump with the Hardin SS pump. Called them but the Hardin SS pumps are backorder three weeks minimum. :faint2::faint2: Hate to not be boating for another three plus weeks!!! Anyone know where I can get Hardin SS pump? |
Pump
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Originally Posted by edb07
(Post 3726830)
...they have none in stock!! |
Try, CP Performance Marine
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Originally Posted by bcoffield
(Post 3726772)
I toasted my impellor and my housing has lots of scratches. I installed a new impellor but cannot get the pump to flow enough water.
I'm looking to replace my pump with the Hardin SS pump. Called them but the Hardin SS pumps are backorder three weeks minimum. :faint2::faint2: Hate to not be boating for another three plus weeks!!! Anyone know where I can get Hardin SS pump? Now I just need to find one for the other motor!! |
Originally Posted by bcoffield
(Post 3736249)
I did find one Hardin SS pump for my port motor. It's now installed and works great. I have noticed after running the boat hard the temp spike is only a few degrees and quickly returns to 160. With the OEM pumps i was getting a larger and longer temp spike!
Now I just need to find one for the other motor!! |
better water pump repair
Originally Posted by techman
(Post 3416528)
I just put in the kits from JC Marine and my historically crappy water pressure improved 100%. Pressures improved at idle and at speed. Engine temps no longer spike when coming off plane either.
Now, if there is evidence that this is a temp fix I will have to keep an eye on it. I'm just glad for the first time in many boating seasons I am starting out with good pressure on both motors. Question for the Hardin Marine folks. Does that stainless steel replacement pump incorporate the quick drain valves of the factory unit? From the picture I don't see the dump valve? |
Originally Posted by techman
(Post 3416818)
If your pump requires the re-use of the original rear housing how does that address the potential scoring on that side? It would seem that your pump only addresses half (roughly) of the problem of the scored pumps.
My OEM pump had scoring in the main housing and the back plate. And the shim kits cover both sides. Am I missing something? |
Originally Posted by Amarket Owner
(Post 3825633)
You need to google im496reb
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Pump repair
Originally Posted by techman
(Post 3416818)
if your pump requires the re-use of the original rear housing how does that address the potential scoring on that side? It would seem that your pump only addresses half (roughly) of the problem of the scored pumps.
My oem pump had scoring in the main housing and the back plate. And the shim kits cover both sides. Am i missing something? |
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