Ok so here is the deal. Boat is running but isn't taking in water like it should. Here is what I've done....and forgive me if I'm using the wrong terms for some stuff. At the water filter water is coming in fine free flowing without the boat on....right after the filter the is what looks like a pump even though I don't think it is if flow freely through that. then after that there is a long hose that takes the water up to the impeller.....it never makes it to the impeller. So I removed the house after the filter that is going to the impeller and put the garden hose directly into that and turned the boat on and the water comes shooting back out towards the filter never making it to the impeller. so i removed the hose on the discharge line of the impeller to make sure it was turning and it was but still no water. next i took the impeller out and there was nothing that looked real wrong with it but I've never even opened one up so I don't know how it should fit or anything like that. I had it replaced by a marinia last winter. The only markings on it was "16". The boat is a 1987 Supra with a PCM engine.
Make sure the raw water filter is screwed on tight with the o-ring in place. It sounds like you have air entering your cooling system. I had a stripped bolt on my impeller housing. I drilled it out bought a longer bolt and put a nut on the backside. Worked like a charm.
Ok so I cann't drill a hole all the way thru, cause there is a screw in the housing on the other side, so I cann't get anything to the other side and get it tight. And i got all the hose clamps and everything tight as can be, and still nothing.