I have a Yamaha 6hp model # 6MSHY that I am trying to find parts for but my model is not listed in Yamaha OEM parts. I think it's a 1999 or 2000 I am having a problem with the motor not pumping water. I installed a new impeller last year worked fine for about 3 months. I pulled the lower unit apart today and the impeller looks fine plus I flushed out but it still not pumping everything look fine.