I have a 2000 yamaha 115 fourstroke and I would like to change the impeller and housing as a general maintenance project.( I bought it 2 years ago and have no idea when the pump was last changed) The water from the pee hole is decent but have no idea on condition of water pump assembly. Has anyone replaced their own? and how difficult is it? I am pretty handy and have plenty of tools. Thanks in advance. Glen
Very little can be known about the condition of a water pump just by looking at the indicator stream. That is only a fraction of the water the system is pumping, many guys think all the water the system pumps goes out here. This is simply a visual indicator to show that some water is being pumped.
Look on YouTube for videos and evaluate if it’s in your capability to DIY it or not. You don’t need to find your exact make/model, the process is similar across most outboards, so if you find a Yamaha that’s close in age and HP, that’s good enough.
I’ve done many water pumps. Get parts and study the proceedure first. With an outboard such as yours, with unknown hours and useage, I would replace this time with a full pump kit including housing, impeller, and seals. In the future, you can just replace the impeller if that is the only part that shows wear. If you operate in shallow water and in rivers, you may want to replace the whole pump every time.
On a motor of your HP, you will need an assistant when removing the lower unit so you have someone to support the LU while you undo the shift linkage and then re-connect it. At a guess, the LU for your outboard weighs over 50 pounds so you’ll need an assistant who can hold it steady.
Be very careful NOT to break off bolts when removing the LU and do not over-tighten when reinstalling. Absolutely go out and buy some anti-sieze compound to put on the bolts before reinstallation to save yourself trouble the next time.
Be sure to grease the splines on the top of the drive shaft to ease installation and future removal.
When reinstalling, take care that you do not trip the gear shift linkage in the lower unit such that you get the shifting off.
The whole process on an outboard of this HP will take an hour after you know what you are doing. Plan on more the first time. Work carefully and be observant. Take pictures of anyting you think may give you reassembly problems so you have something to reference.
Grouse
Glen,
You can use Yamaha’s web site as a resource.
If you look under “Care & Maintenance” then “Parts Lookup”, you will be able to look up your model and find a schematic,
under “lower Casing Drive 1”. It’s a great way to find parts you need.
I have done this when replacing my water pump on a Pro 60 2 cycle.
It’s also helpful to have someone to help with the lower unit as they can be awkward and heavy for one person especially when putting it back on.
For what it’s worth – I replaced an impeller on a Yamaha 20 hp 4 stroke a few years ago. A year or 2 later it was obvious that it needed a new one already. This time I took it in to see if there was something I was missing. The mechanic told me on Yamahas he always replaces the sleeve and the impeller and said even though it looks shiny and perfect he still replaces them cause he’s had too many fail before they should.
I know some replace the impeller every year as a precaution but I don’t think that’s necessary unless you’re running the motor shallow a lot where the intake would suck in a lot of mud, sand, etc.
I did my 115 last summer, and not really all that hard.
Checked out the great videos on u-tube.
Got a few questions answered on a thread here:
http://www.in-depthoutdoors.com/community/forums/topic/equipment_1337246/
Only issue I ran into was my key that held the housing in place was frozen into the shaft. Took a little screwing around to get it out.
There was another thread that I would pay attention to, but I can’t find it. Covered a squealing noise that came from mine (a Yamaha 115 issue) after I was done… and others had had it happen, either just randomly, or after servicing. The fix involved a Yamaha made grease for the shaft I found in stock, and ordered from the Skeeter Boat Center. On the shaft, there is a brass bushing (you can see it in the parts breakdowns) that it rides on below the spline. There will be a shinny area on the shaft as well. Greasing the shaft there helps. Feeding, like a shot gun cleaning tool up to the brass bushing with the grease on a small piece of greased rag fixed it. The noise would only come after a long hard run, where it got hot. As said it was rather common, as a half dozen guys were in on the conversation, and the SBC dealer guys knew of it, how to address it, and stocked the grease.
I would just lube this as described right away when you have it apart.
The pump kit does not cost much more than just the impeller.For a 50HP,it was only about 8.00 more.
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