25hp water tube pressure (2001)

[greg hodgen]

This is a 4 stroke yamaha. My odd non merc. Changed my water pump, put back together and just sputtering out of the tell tail. Took back apart and tried blowing through water tube and there is major back pressure. There was a little piece of rubber in the pee hoole that i removed but still much more back pressure than i would expect. After removing the rubber (big enough to plug tell tail), I think I have it, put all back together and the tell tail is still not steady. Looks like there is still a piece of rubber somewhere. I took all the lines apart on top while blowing. My questions. Could the thermostat be a problem. I suspect that a big piece of rubber made it up the tube and is stuck somewhere...what now ? Is it normal that there is back pressure on the tube/system.
Thanks all for reading

[boats.net]

No should not be any back pressure. Chances are you lost one of your impeller blades or at least part of it. You should remove the thermostat and blow as much of the water passages as possible.