Yamaha 25 water pump issues

I installed a new water pump kit on my Yamaha 25 2 stroke and got about 1 year out of it before it seemed to stop working properly. Got a new kit and installed it along with a new thermostat. It runs fine for several minutes before it stops pumping water. Removed thermostat and ran it hooked up to the hose and I get the same thing. Seems fine for several minutes and then no water flow. Doesn't appear to be a bad thermostat. The impeller that I just replaced really didn't look bad to me. Not sure what could be causing the issue. Any ideas?

take the bottom of connect a garden hose to it , take the thermostat of and turn the hose on if water comes out where the thermostat is and comes out of the pea hole it is ok if it does not come out of one of them there is a blockage . if they come out of both ok then your block is fine ,the problem is your water pump . check below your water pump to see if there is anything causing a blockage, if ok its your water pump it is drawing to much air. renew your water pump .every one just replaces there impeller and forgets to renew the rest if needed

Thanks. Did exactly that and getting no flow so I'm on to looking for blockages

piece of nylon strimmer wire down the pea hole ? whats the compression ?