PA.WOODCHUCK

This spring doing the pump/impeller replacement since has about 100hrs in 3 seasons. stock w/engine number 0M084807 2002 496HO.
1- impeller if housing looks OK
2- impeller and new housing
3- kit with wear plates

Another issue I have high water PSI, close to 40psi. So far have checked PS cooler, replaced HE gaskets, new sensor. Before I dig deeper into oil cooler hoses are there any places on the output side of the HE which may cause this issue?

​​​​​​​Opinions and part numbers please Thanks

1Zoom

A great option if it needs a complete pump is the stainless one from Hardin. (Hardin Marine - Stainless Steel Gen 7 Plus Sea Pump for Mercury 350, 496 and 502 Mag (hardin-marine.com) They also offer a rebuild kit with a stainless housing, (Hardin Marine - Hardin Gen 4 Overhaul Kit 625-4178 (hardin-marine.com).
As for any places to look for restrictions check very closely in your coolers down line from the pump. In many cases pieces of the impeller get washed into the coolers when they disintegrate, many times I have had to fish out remnants of impellers using mirrors and long nose pliers.

87MirageIntruder

On your 496HO the first area of a possible restriction after the seawater pump is your oil cooler. The water goes through the steering cooler before the oil cooler, however the steering cooler is a straight open pipe without a "grid" to catch items. So, check your Oil cooler first, then the heat exchanger (power steering side of the engine end cap).

Keith Atlanta

Yeah, what zoom said. Personally, I got 2 rebuilds out of mine then started to chase issues, thats after about 400 hours on the pump housing. At 400 hours, I was happy, I went back to a stock pump as a replacement. That being said, I think once you get up there in hours, you should flush forwards and backwards with a calcium removal flush, I did it with one from west marine and one with 20% muriatic acid and water in a bucket with the old impeller then mocked up a junk transfer pump from Harbor Freight and did it backwards. THEN put in the new impeller. The stuff that comes out will blow your mind! There a couple write-ups in the Hull Truth which is where I got the idea. As these 496's get up there in hours I think this is something more people need to consider. Salt or fresh it doesnt matter, salt creates salt and calcium build-ups but freshwater lakes create some hard water calcium build-ups that are actually worse (according to the article). When your done, if you take the end caps off your closed cooling log it looks like new.

PA.WOODCHUCK

I'm not sure I want to go hardin pump yet. engine is fresh water with only 220 hrs. But still open once I pull the oil pump off this spring.

boostbros

i used a couple of the all brass pumps from amazon worked much better than stock there was a blow down drain on the original it pumps better at low speed to and that helps the fishing boats with a weird water bypass that was plugged with old impeller bits the pump from amazon is fairly well cast and machined and is holding up well after a few hundred hrs it also pumps more water at idle where the fishing boats live most of their life