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Question on water pumps

SuperT

Regular Contributor
Is there a rule of thumb about how old the water pump is in your motor, that it would be time to replace it even with very little usage ? I'm referring to the known number of years since you've replaced or had it replaced.
I'm not talking about a motor that service is not known to you. Just curious.
 
Impellers are like tires.----They are all black but they are not all the same !------A new impeller should be installed every 5 years.------Some motors sooner.-----Just think , there are many smaller motors that do NOT have a warning or shutdown system.------They will run till they go BOOM.----Learn to install a new impeller as they are cheap !
 
Impellers are like tires.----They are all black but they are not all the same !------A new impeller should be installed every 5 years.------Some motors sooner.-----Just think , there are many smaller motors that do NOT have a warning or shutdown system.------They will run till they go BOOM.----Learn to install a new impeller as they are cheap !

Thank you, that's just the information I needed.
Have a good day
 
That is right, impellers are cheap. Better to change it often. What comes about the whole pump assembly, i (think) that i have original pump assembly still in my Evinrude (from 1966). During rebuild, i made notice that pump assembly is no anymore perfect, some corrosion but not too bad. I am thinking to buy new pump assembly. My Mercury have still original pump assembly, from 1977 and it is very good condition still.
 
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Pump assemblies are different too.-----Some such as the older OMC are aluminum and a skilled individual can refurbish them to new dimensions on a lathe.----Some are plastic housings that suffer from extreme exhaust heat.---Also from lack of cooling water to impeller the plastic housings are damaged.-----Regular inspection is very important !
 
The engines I'm talking about are:
1957 Evinrude 3hp Lt. Twin
1982 Johnson 4.5hp
1986 Johnson 15hp
1995 Johnson 70hp
They all have had impellers changed in the last 5 years but it's getting time to consider refreshing them. That was the reason for the question.
 
I like the tire analogy, Racer. Rubber is not real rubber anymore....it's a synthetic mix. Impellers are not the quality they once were. I have many early OMC's with perfect impellers yet that are 50 years old. I replaced the auger drive belt on my 1970's vintage Toro snowblower after the original belt failed a couple years ago. Tried Kevlar, tried Toro OEM, they are all failing. Why? Nothing wrong with bearings, alignment, pulleys, gearbox, auger, or operating techniques. The replacement materials are simply not as good as in the 70's. Tires now are not made to last timewise. They are a composition that contains more synthetics. They are engineered for high miles, not like back in the "old days", when the average car or truck was used 10,000 miles per year. My 1976 Case backhoe loader has the original rear tires on it. I bought a new set of front tires 6 years ago and they are already full of cracks........modern materials used to make rubber compositions are inferior. Also, going back to impellers. Engineers have made water pumps higher pressure, in part by using tighter bends and shorter vanes on impellers. This further stresses the material as it rotates inside the housing. Vanes break down faster. Impeller designs are all different. The longevity will vary, depending on pump design, operating and storage conditions, as well as impeller material quality. As mentioned, pump housings must be considered because they can get pitted, depending on composition material, or distorted from wear or heat. So, it is very difficult to give you a certain timeframe for replacement.......yes, just like tires, Racer.
 
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Similar topic. I was just trying to find out what is a good indicator of a good pump. I just started my engine up for the first time since I bought it, and after replacing the pump. I do not know what I am looking for. I heard my 40 hp Sea Horse will spit water rather than have a constant stream like the newer boats. But after starting and running for a minute, There is just exhaust smoke and a very small amount of spitting water. Maybe the thermostat is not open yet, but I did not want to risk the engine. What should I be looking or waiting for?
 
Toadshape.----Get behind your boat and 40 hp on waterskis.------Observe the water POURING out of the exhaust relief where you now see it spitting.-----Once the boat is stopped you will see it pouring out in a small cloud of steam looking vapour.----Then when motor cools it will spit out again.----Put a new impeller in that 40 HP every 5th year at least !----You have tested your overheat warning light I hope!----Or consider installing a buzzer which can be heeded when you are scanning the beach for 2 legged deer.
 
Nice. I have it in a barrel in the back yard right now. Not really convenient but I hoped it would tell me if I installed the pump correctly. The head got pretty hot after about 2 minutes of idle. I splashed some water on it and it steamed off. I still haven't replaced the thermostat so I guess I should do that to make sure. Since I do not know this engine much at all, I do not know where an overheat alarm would be. I know I do not have any light on my dash. I looked around in the manual and I cannot find it under any of the headings I looked at.
 
The steam indicates that is running way too hot.---Stop and investigate now !------So answer this , was the water in you barrel 6 or 8" above the pump , yes or no.----And you must have the thermostat installed in that engine in order to run it.
 
Well, I found the light. It was deleted and covered up. Guess I have another project. Turns out the temp switch is no longer made so I need to try and find an aftermarket.
 
I just removed the thermostat and it is bone dry. Does that indicate that the thermostat was just simply closed, maybe stuck closed, or would water have made it up there if the pump was running correctly? There is a sign that mud daubers have been on the engine. Is there a good way to test if the line is clear, or force some air in there to make sure it is clear?
 
Try putting the thermostat in hot water, it should begin opening at about 145 degrees. Start motor with thermo out. Water should flood out opening. Mud daubers can't get between water pump and powerhead. It's sealed off.
 
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Great idea thanks. I just read some other threads talking about mud daubers clogging up water inlet tubes. I did not see any evidence when I installed the pump though
 
Hard to make a mistake on assembly of the pump in my opinion.----They are dead simple.-----I coached the 8 year old grandson on how to install an impeller on his 10 HP Johnson.-----When you installed the lower unit were the 2 water tubes in the exhaust housing or in the pump ?
 
Yes. That along with the shift wires and shaft were really fun to re-install all at the same time. But now that I have done it, I could do it again pretty quick. The only thing I keep second guessing is if I put the rubber pump back in the right direction. I don't know why. I am sure I did it right, I just have this doubt and it is bugging me. When I took the old one out it was completely trashed and the key was even out. Can't believe the engine still runs at all. Who knows what damage could have been done. The shaft was also pretty scored and somehow it was dinged up with knicks in places. It is obvious someone else replaced the pump at least a few times and did not do a good job. Can't imagine how you ding up the shaft like it is. I am surprised the engine doesn't vibrate right off the boat.
 
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