My boat has a 2011 Yami 25 hp. tiller. Hasn’t been used much and seems to be pumping water with a good stream. Would be foolish to have a new water pump installed even though it is showing no problems? Peace of mind for the next time I launch on the Miss. I’m not a do it myselfer.
Assuming it’s never been changed before (or you don’t know when it was last changed), no it would not be foolish to change the pump or at least the impeller.
This is not a difficult job, nor should it be very expensive. The one thing I would add is make sure before reassembly that the lower unit bolt threads are coated with anti-sieze. Having a lower unit bolt seize and break off creates a whole bleep show that is so easily avoided with 1 dab of AS compound. You’ll thank yourself the next time the pump needs to be changed.
I change impellers every 5-7 years depending on how much use they get. That seems to be plenty often for my levels of use and where I run the outboard, I notice very little wear even after 7 years.
You can’t count on signs of problems to determine when you should replace the pump. The pump essentially over-supplies the motor, so even a very worn pump may supply a steady-enough flow so there is no visible lack of flow from the telltale or indicator nozzle.
The main thing you’re trying to prevent is a total failure of the impeller where a vane breaks off and blocks the riser tube, cutting off flow to the engine.
Grouse
Grouse is right on. The rubber the impeller is made of hardens with age and can become brittle breaking off chunks. Since we are on topic related to engine cooling I had a case where my motor ran too cool, gravel caused thermostat to stick open.Resulted in my oil looking like a milkshake in fall. All from crankcase moisture not being eliminated by normal temps especially in fall with lots of trolling, well over a pint extra. I thought it was head gasket! 70 horse 4 stroke Evinrude(Suzuki). Thermostat replaced AOK!
Hey question guys,
Do you just change the impeller or do you get the whole kit with the gaskets and impeller?
get the kit, it does not cost that much more and you get the wear plates.
the ones I have done you can see wear on the plates and I believe that will wear the impeller out faster.
plenty of videos on how to it….
Do you just change the impeller or do you get the whole kit with the gaskets and impeller?
Either or.
Only rarely is the very rarely is the impeller housing and gaskets needed in a freshwater outboard. If running in silted rivers or saltwater, replace the entire system every time. Just run your finger on the steel liner where the vanes of the impeller run, if they aren’t shiny smooth, then replace.
I’ve been doing water pumps for myself, family, and friends since the early 1990s and I’ve had only one outboard that had a bad impeller housing and really needed the whole kit. That outboard was bought off the internet and it had obviously been run in saltwater.
Personally, I just buy the impellers and then if I tore it down and discovered a bad housing, I’d order the kit when actually needed.
Grouse
I have learned to use a kit to replace the water pump on my Optimax gets changed every two years as the heat from the exhaust hardens the rubber in the impeller. Impeller looks perfect until you try and move the rubber it is hard as a rock.
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