At the end of the season, I tried to winterize my BZ602. I tried to suck antifreeze into the engine (as I have done every year), but nothing would suck. I reconnected the raw water and the pump worked fine pumping water through to the the exhaust outlet. I tried the antifreeze again... Nothing. This time, when I reconnected the raw water... Nothing. I ended up draining the system for the winter.
Now I am trying to figure out why the raw water is not pumping through the engine. Impeller is one season old and looks great. The Impeller turns, so the pump seems to work ok.
You may have one of a number of issues; 1) the back of the heat exchanger may be blocked with crud. Remove the aft cover on the heat exchanger tank and inspect. If there is weed and or bits of zinc in there, clean and reassemble. 2) There may be a break in the gasket (or "O" ring) on the cover plate seal of your raw water pump. This will cause the pump to suck air which is easier for it to do than suck water. Replace the seal (gasket). 3) there may be wear on the body of the pump or again the cover plate so that the impeller is not squeezed between the back of the pump and the cover plate. 4) the impeller may have a loose insert. This would allow the shaft to turn and not the blades. 5) the hose that you are using to suck up the anti-freeze may not be seating properly on the intake fitting on the pump. This will cause the pump to suck air. Check carefully and you should find the problem. Please let me know how you get on. Regards, Stanley
-- Edited by Stanley on Saturday 14th of March 2009 10:46:45 AM
Ok, Stanley. I finally got down and got her running. I did remove the heat exchanger but no visible blockage - but what a PAIN! There has to be an easier way to get that thing back in. I'll pay to have it done next time.
Anyway. Cleaned up the impeller cover and double checked seals. Opened and checked seals on the raw water strainer. Replaced pencil zinc. The pump worked!! I have a feeling it was sucking air at the water strainer, but Im not certain since I fixed everything at once.
So, thank very much for the advice and here's to warmer weather so I can get out on the water.
