After not having my boat in yet this year, I put it in today and had no water pressure on one side. I've read that there may be a check valve in the system. I have 525 motors. Where would I find this valve if present? Any other thoughts? I removed the hoses and placed my hand on the intake but didn't feel any suction, should you feel some suction?

I forgot to add that I have bravo XR drives. I was thinking that if the check valve was between the drive and the pump I could put a vacuum on the hose and try to suck open the check valve if it is stuck.

Sounds more like a bad impeller.

x2

Thanks. I talked with Mercury Racing yesturday, and they confirmed that there was no check valve between the drive and sea pump. I have to say it was a good experience talking with them. They gave me the part number for the impeller and told me some other stuff I had questions about.