Water pump bad?

Homerr · Jun 22, 2002

My boat has been sitting most of the spring. I went out to clean things up and top of fluids, etc... For the upcoming vacation. I have a 5.0 Mercruiser (305 Chev) I started the engine and noticed water leaking near the bottom radiator hose coming out of the water pump. Thinking it may just be that hose loose, I tightened it a bit, but it didn't seem to help. I probed a bit further and noticed there was water coming out of the 'weep' hole in the bottom of the water-circualting pump. Not a lot, but some. More or less a dribble or oozing. You can also tell that it has been leaking there for a while due to the rusty deposits on the pump where the water has been running. After approx. 3 to 5 minutes of running the engine, the leak completely stopped. I know on cars, there aren't suppose to be any leaks! Is my pump bad? Why did it stop leaking? And most importantly, can I trust it? Thanks, H.

sea wolf · Jun 22, 2002

Re: Water pump bad?

i'm not sure, but i believe that small leak is normal. i think i read that in another thread. i don't own a merc, so take it with a grain.....

Homerr · Jun 22, 2002

Re: Water pump bad?

I actually called the dealer as it is under warantee. He said it is 'somewhat' normal, but to bring it in anyways and they'll replace it. Apperently when they sit for long periods, the seals shrink up a bit and close after you fire them up after a long sitting time. Don't know if this was a line of garbage or what, as he was eager to replace it. He says they've replaced their share about once per year with the same problem. I can't gripe too much as I think those pumps are a couple of bills! H.

Trent · Jun 22, 2002

Re: Water pump bad?

Garbage...........They dont leak! Its leaking around the bearing/seal. If its under warranty let them do it!!

Homerr · Jun 22, 2002

Re: Water pump bad?

I agree guys... I took it down this afternoon. Let the dealer play with it. Just for giggles, I looked online for a new one. They aren't as bad as I thought.. $137 from the dealer, and around $120 everywhere else. My question now is, why did it fail so soon? I honestly haven't had it out that much. Had it in salt a few times, but I've always flushed it when I got back to the campsite. H.

Trent · Jun 22, 2002

Re: Water pump bad?

Thats sort of like asking if Microsoft "ME" is better than XP.....I dont know!

f_inscreenname · Jun 22, 2002

Re: Water pump bad?

If you leave it sit a lot the seals in the water pump dry out. The only lube the rubber seals gets is when water is pumped through the water pump. Every thing drys out if you leave it sit.

Homerr · Jun 22, 2002

Re: Water pump bad?

I agree it dries out, but the last time I ran it was in late March. Wouldn't think it would do that in such a short time, but then again, it looks like it's been leaking for a while. So what can a person do to prevent this during storage other than a fresh H2O system? Thanks, H.

Spidybot · Jun 22, 2002

Re: Water pump bad?

Even though I agree it should not be neccessary for short storage, you could flush with plain water and then add some ordinary coolant to it. Coolant preserves and lubes waterpump etc. If you store the coolant mix you can reuse it.

Homerr · Jun 23, 2002

Re: Water pump bad?

The more I think about it, I really want a closed cooling system. It's really the best way to go. How do you add coolant to it? Is there a hose attatchment or ? I think I read about an attatchment of some sorts. Thanks, H.

f_inscreenname · Jun 23, 2002

Re: Water pump bad?

It is not to ask why. It just happens. Sounds like it was going to happen any way. Leaving it sit just brought it on. Fix it,don't worry and move on. Things like this happens. I had to change a water pump on my van that was only 2 years old (closed cooling). I would'nt change to a closed system. To much BS. $30.00 for a new one and a couple of hours and you are on your way.

Homerr · Jun 25, 2002

Re: Water pump bad?

Well, got the boat back today. New pump, and she's ready to go. F_inscreename: Where are you getting a water pump for $30? The cheapest I found one for a Mercruiser 305 so far is $89. Mercruiser Parts Express wants $137 If I can get 'em for $30 bones, then I'll stock up on a few. H.

f_inscreenname · Jun 25, 2002

Re: Water pump bad?

Go to your local auto parts store. I bet you can't find any diffrence. Some say there is but no one has been able to show me. I hate it when I have to go to a marine parts store. "You must use mercruiser parts on our motors" horse poop.A 305 chevy is a 305 chevy. If you are lucky you may get some beefy valve springs but the rest is just bolt ons.

Spidybot · Jun 26, 2002

Re: Water pump bad?

f_inscreenname, If only you were right. Turning an engine from auto to marine involves more than just putting 'marine' after the name. Some parts are the same but not all. Especially electrics, securing fittings and fuel hoses are different. Sometimes even cooling/water jackets. Much of this relates to the different working conditions in a closed compartment. Homerr, You can add coolant to the water either if you run it in a barrel or by disconnecting the hose from the transom and put it in a bucket with the mixture.

f_inscreenname · Jun 26, 2002

Re: Water pump bad?

Hay UU No dissing but.... A 305 is a 305 chevy. I have taken many apart and rebuilt a lot better. All you have to do is find the part # (say off a water pump) and you will see there the same. You are right ,there is some diffs. Electrics (wire and alt),carb,dist cap but like I said a 305 is a 305. Mercruiser buys motors from the same G M factory that makes motors for Chevy trucks. Everything else are mercruiser bolt ons.

Trent · Jun 26, 2002

Re: Water pump bad?

Sorry guys, but their is a difference in marine waterpumps and automotive! A marine pump has a special ceramic seal, stainless steel backing plate, and a bronze impeller to resist corrosion. An automotive style pump, with its stamped steel impeller, would fail due to corrosion in a short time.

oldboat1 · Jun 27, 2002

Re: Water pump bad?

But in any case, aren't we just talking about replacing the impeller? I'm still more familiar with outboards, but I'm about up to the point where I really should service the waterpump on my Chris Craft -- with a 305 Chevy inboard. It must be more that just the impeller if the parts cost is about $140 (?)

russellackland · Jun 27, 2002

Re: Water pump bad?

I have a Fresh water cooling system. If you use the boat in Saltwater........it is the only way to go. As for the difference in circulating pumps, if you ARE NOT running raw water (salt or fresh) through it, only coolant, why do you need all the specail stainless, ceramic and bronze parts of a "marine" pump? I suspect that there is no good reason to spend extra money on a "marine" pump, depending on your engine configuration. In fact I replaced mine last year, bought a high flow circ pump from summit racing parts for a ford 302. could have gone with the cheaper one though.....didn't tell'em it was a marine engine and I didn't see a difference from the old one that i took off. (makes me woner about the "high flow" part) russell

oldboat1 · Jun 27, 2002

Re: Water pump bad?

The closed system cools the engine block and the raw water system cools the exhaust manifolds (and transmission oil, where appropriate), and provides the cooling (heat transfer) for the closed system. Boats don't have radiators like cars.

RandyJ · Jun 27, 2002

Re: Water pump bad?

Just a note here. One difference in boat/marine engines is that they supposedly are designed to run at high RPM or even wide open throttle for long periods of time. Where a fiber or nylon part would be sufficient in an automotive application it may not last long in a boat. I just replaced timing gears in my old 140 and I would bet that it would last longer with steel gears rather than the fiber type gears.

Water pump bad?

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