OK - similar problem I have. New to us boat - a 1980 Irwin Citation 34
Motors perfectly - always starts, always spits water.
Twice - sailed and then when starting the engine hot light soon came on and no water was coming out.Both times, took the hose off, looked at the impeller - everything seemed fine.Let it cool - started it up and everything was fine.
Uggg! If you come up with a solution - let me know.
If you look back at the post, I found the problem was me! However someone responded who heeled over so far it exposed his intake and allowed air in (though, someone else stated the pumps are self priming) On some boats big seas might also do it . If air is getting in your intake, I think opening the line at the impeller (as you did) would allow the air to bleed out (but then, I'm no mechanic!). If this was the cause, closing the intake while sailing would cure it. BTW, whenever I close the intake valve, I always put the keys near the valve, so I have to go there (and open the valve) before starting the engine. Many others probably know this trick, but everyone I've shown it to is impressed (as was I when someone showed it to me). If you respond, please do so in the thread, as I will get it, and others will benefit as well. In fact, I will post this email. Hope thats ok.
Last edited by L124C; 08-17-2009 at 02:50 AM.