Yamaha 2.5 impeller

[MADRIGAL]

Can anyone tell me how I would inspect or change the water cooling impeller on a 2010 Yamaha 2.5 HP four-stroke outboard? Where is it located? I don’t think there is a problem, but I would like to do any maintenance before there is one.

 

[VicS]

Can anyone tell me how I would inspect or change the water cooling impeller on a 2010 Yamaha 2.5 HP four-stroke outboard? Where is it located? I don’t think there is a problem, but I would like to do any maintenance before there is one.

The pump is located on top of the gear case

The gearcase wiil have to be removed to access it

It will be necessary to disconnect the two halves of the gear shift rod from each other. The clamp is accessed by removing the rubber plugs in the side of the "leg". It would be sensible to mark the position of the clamp on the rods to aid reassembly

The gearcase should come away complete with vertical drive shaft, leaving the water tube in pace

The pump housing can be slid up the drive shaft to remove it followed my the impeller ............. retrieve the drive pin

Parts diagrams give a pretty good indication of what is involved

Yamaha Outboard Parts by HP 2.5HP OEM Parts Diagram for Upper Casing | Boats.net shows the rubber plugs

Yamaha Outboard Parts by HP 2.5HP OEM Parts Diagram for Control | Boats.net shows the gear shift rods and the clamp

Yamaha Outboard Parts by HP 2.5HP OEM Parts Diagram for Lower Casing Drive 2 | Boats.net shows the water tube and the general arrangement of the pump and drive shaft

Yamaha Outboard Parts by HP 2.5HP OEM Parts Diagram for Lower Casing Drive 1 | Boats.net Shows the components of the gearcase including the pump in detail

The bit that may tax your patience the first time you do it is getting the splines at the top of the drive shaft to engage with the splines in the crankshaft on reassembly ( Gently turning the prop with it in gear , should do it)

If you are tearing it apart to inspect the impeller fit a new one anyway if its more than a fe w years old

 

[MADRIGAL]

Thank you for that detailed description of the process. That is just what I needed to know.