so everyones telling me that i need to put in a new water pump in the engine i just got ('78 johnson 70hp). From what i understand, the impeller should be replaced once a year. I think mine has been in there for just over a year. my first question is... is the impeller and the water pump the same thing? 2nd question is, how long should the water pump, or the impeller last? is there a limit that you shouldnt push it past? why does it need to be replaced so often? how can you tell if its getting close to time to replace? i hope the engine not peeing isnt the only sign... last question is, should this water pump issue be giving me this much stress, or is it really just more of a maintenance thing?

thanks!

You just need to stop worrying and simply replace it at least once every two years if fresh water only or once a year if it sees salt water. The impeller is the actual rubber part in the water pump housing that moves water up to the motor. The water pump is the entire assemble. If it goes out, you are very likely to ruin your motor. The need to be replaced because they are made of rubber and they get hard, break, and then your motor overheats.

When folks start talking about how to know one is going out, they will usually refer to the water pressure generated by the impeller. This is only a reference point however. Pressure does not cool your outboard, flow does.

My advice, change it now and then follow a regular schedule after that.

impeller and water pump same thing.

i change mine every two years and have never had a problem. If you learn to do it yourself, its much cheaper. I have a buddy that hasnt changed his in eight years.

i dont know if you can tell when it is time, until it is to late

Yes, the water pump and impeller are one in the same.

My Mercury shop manual says to replace it every 3 years. Some guys replace it yearly, others every other year. When they aren't used very often, then rubber impeller can take a set and it won't pump as much water as it should.

everyone on this forum is so helpfull!! thank you all so much for answering my probably rediculous (and probably endless) questions.

The most overlooked or neglected thing is the thermostat and poppet valve. They need service too. Impellar every other year and complete cooling system service every four years. Check the heat alarm when servicing the cooling system.

Look at it this way, an impeller is $25-75, and maybe $150 to replace it. A new block is $5000-15000 not counting labor.

Which would you like to replace more often?

If you run your engine out of water, then replace it every time you start it out of the water. If you run your engine in fresh water AND you stay away from sandy areas you can get away with every 2-3 years.

If you run sand areas of water or saltwater every year.

I'll error on the safe side and change mine every year.

you can replace only just the impeller. pump housing needs replaced if the inner housing is scored *at all*. OEM full kit is about $60 at Fore & Aft.

they can last a good long time - I bet there's pumps out there 10 years old still pumping - but the downside of failure is catastrophic. I go 2 or 3 years usually.

I reasealed my L/U this winter, the impeller , 1 1/2 years old, looked like brand new, the vanes straightened out after a few hours. Reinstalled it and plan on giving it two more years.

The other thing is, after you replace this one, you'll know how strong the pee stream is with a brand new impeller - so if it starts to weaken, you can recognize it and take action.

Water pump kits or just impellers, and for that matter all parts seem to me to be cheaper at boats.net. Way cheaper. Call Calaveras lake boat repar for an exact quote.210-635-8687. I'm a customer there once in awhile.

i replace my entire pump every other year ,cheap insurance i dont want to find out the lifespan of a water pump