Water pump

This may be a dumb question but I gotta ask it:

I have a '73 Ski Nautique with a 351 that overheated this weekend.

Does the water pump on the front of the engine function or is it just a cover and receptacle?

It has a pulley but I'm just wondering why have two: impeller and regular pump.

   

Oh no, I know better than that. Thanks, I suspected as much on the two pumps but wasn't sure after getting it off and looking at it, especially as loosely as it turned. I haven't had any problems and we've been on the water 4 or 5 times over the last couple of months. We were headed up river on Saturday, I'd say about 25-30 minutes into the trip north doing about 35 mph and I heard a high pitched noise gradually get louder. The water temp indicator read about 150 which was unusual so I eased off and kept it at about idle speed but sped back up for a bit so I could look out the back to see if water was flowing and its was, not sure it was enough though. I raised the engine cover and had my wife cut the engine. I saw a puff of smoke from the oil cap which really scared me. I could tell it was hot.
I just got back from the marina and they'll have to send it off for rebuild. They tell me I'm down for a week. I hope it doesn't end up being the RWP when its all said and done. It is 38 years old after all and may need rebuild just for good measure. I try to keep on top of things but didn't see this coming.

All I have is a water temp gauge. The highest I saw was 160 after I shut 'er down. I've never seen it much more than 100.
I don't know exactly where that is measured but I figured it would rise after shut down with no water running thru the engine. The radiating heat was more than I've felt before so I know it wasn't normal.

If you never saw more than 100 I'd dare saying you are running without a thermostat, 160 wont damage the engine.

This is all considering the gauge/sender are good.

Greasy Lake wrote: Hypothetically, what would be so wrong about running our boats without a thermostat?

Not given,
The marine engine industry learned way back in the 40's that engine temps need to be controlled to maintain efficiency as well as oil viscosity. If you need to run without a T stat, you have a problem that needs addressing.

Any tips before I get started on the water pump?

Not sure what the extra screws are for:

http://s1211.photobucket.com/albums/cc430/house777/Boat%20Pics/

73SN wrote: Any tips before I get started on the water pump? Not sure what the extra screws are for: http://s1211.photobucket.com/albums/cc430/house777/Boat%20Pics/

It sure would be nice if we new knew if you are concerned about your RWP or the circ pump!! Your attempt at trying to provide a link flunked BIG time!!!


What extra screws?

Pete the images showed up for me... pics

The 2 screws hold the backing plate on the water pump. They go side by side on the top I think. Make sure that your mating surfaces are very clean. Had to redo mine since the gasket was leaking like a sieve. I also broke a bolt over torquing it and had to start all over.

Green plastic pump?   Maybe painted red?

Look inside!   Maybe Toast!

Gary S wrote: I hope it's not that pump you took to the marina.The only things that go wrong with them is either they leak out the weep holes or get noisy. Some older marine engines don't even have those pumps,they rely only on the raw water pump.

That was my original concern about having a RWP only. Wish I'd have popped open the old pump before I dropped it off.
I was trying to rush and get the kids wakeboarding before summer vacation is over.

Better change marina's fast. Water always flows thru the exahust,otherwise the rubber or in some cases fiberglass,would get hot and burn thru leaving you at the bottom of the lake

And, next time you talk with your Marine mechanic, make sure you ask him if he once worked at Sears Automotive Center.

Water by-passes to cool exhaust, so that it doesn't turn a '73 SN into a pretty habitat for fish.

Thats ok Paul,you don't learn anything if you don't ask.We just don't want to see anyone taken advantage of.

I've learned a good bit taking this beast apart... hate to look back at old posts now but thought this one would be a good one to revisit on the raw water pump. I figured it'd be a good time to replace some innerds while I had it apart. can anyone tell me about this type and where I can get an impeller? The rest looks good but the rubber is a bit dry rotted on a leg or two: (I've had it 8 years now)

Pics: