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Originally Posted by Plowtownmissile
(Post 4089619)
If you have a DWP lower, make sure the nose is properly sealed off. This may seem obvious but I know several people that have smoked impellers because they forgot to do it.
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start it and crack the throttle a few times on the hose, before I fixed it that's the only way it would flow, good luck
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Originally Posted by Tib
(Post 4089600)
I know this is an old issue but I have a question... Can the water drain system (actuator) on a 496 MAG HO in any way cause the sea water to shut off from the sea water pump? I recently changed the impeller and serviced the boat for the upcoming season and now I am not getting water to exhaust. The old impeller worked fine before the change because I started the boat to heat up the oil before I drained it. I only changed impeller for cheap insurance. I've tried everything in the forum... blipping the throttle, pulled and checked impeller rotation and condition, supplied lower presser on hose to muffs, and cracked bleeds downstream of pump. I am pretty sure it is the grooves in the housing (396 hours) but hate to change housing or rebuild it if it could be the actuator? I also know there is not an outside source (seaweed, rubber) blocking the flow since the old impeller was perfect and the pressure was good before the change. Any info would be fantastic!!!!
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ok thanks. I will look into it but I think the only fix is going to be either a rebuild kit or new pump. I was hopeing that valve may have something to do with it. Down here next to the Gulf of Mexico we don't "winterize" our boats. Really no need for the water drain system...
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Anchor that is very interesting and I will check that!!!!
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Originally Posted by Tib
(Post 4089655)
Anchor that is very interesting and I will check that!!!!
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Originally Posted by Knot 4 Me
(Post 4089604)
If it was the grooves in the housing then why did the old impeller work just fine? Are you giving it plenty of time to get water throughout the system so it comes out the exhaust?
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Get one of the rebuild kits with the stainless steel stamped inserts. Still think this is the most cost effective way to rebuild sea water pumps and I personally think they are better than stock once this is done.
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If you have a sea strainer you may have to fill (prime) it first.
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for a while over 2 years worth - Mercruiser had a lot of priming issues and overheat problems with the impeller out of tolerances for the Gen VII water pump. To find out if it could be your impeller pull the one out of the housing and buy a new one on the shelf currently from a stocking Mercruiser dealer because they should be totally cleared by now from those stocking dealers.
Take a caliper and measure to see if there is difference in your measurements. At least you will know that could be your problem. When I got the SB from Mercruiser I check all of mine on the shelf and had few to send back to Merc.. I posted this up here back then and here is more of the jist for anyone that might have interest. Link is below. Good luck if you need more info just ask because during that timeframe we measured the impellers & hosings and always thought something was just hair off but how could that be Mercruiser is always right. Right..... http://www.offshoreonly.com/forums/g...8-headsup.html |
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