I had a problem with my Yamaha Enduro 15hp 2 stroke outboard motor cooling system recently. It wasn't peeing at all. A quick check confirmed that it was clogged but I wasn't sure if the impeller was damaged as well and so I decided to unclog it with a bicycle pump first. After unclogging it and started up the motor, I found that the impeller was working fine. It has a strong pee!
This is a quick fix and may not be a long term solution. If your impeller is damaged you still need to replace it. I also suggest that if you decide to try this out, just be extra careful not to exert too much pressure as this may cause water leak from other parts of your motor.
