over heat

[pepmyster]

Good day. I'm at my wits end. In the spring, I replaced both my engines impellers as preventive measures. Now, the port engine is okay and the start board engine will not suck any sea water. Checked all clamps and such. Was working perfectly before the change. If I run it with water to the service port, no problem. Does not overheat. With the sea water, over heats. 2004 VP 8.1. I replace the impeller again, thinking maybe it's defective. Nope, same thing. Any insights would be great!

[Coldcruisin]

Have you checked your sea strainer and intake for blockage or obstructions? Seacock ok? Cant pump water that isnt there. Keep us informed.

[pepmyster]

SeaCock open, strainer pure clean, able to push water out, wont suck back in.

[km1125]

Is the cam still good in the pump? Have you manually rotated the pump with the output hose off to see if water flows? (it will be slow but certainly should move some water).

If you've done the tests above then the only other thing would be a decent vacuum leak allowing water to enter between the through-hull and the pump. Sure everything is locked down? Typically it's just the top of the strainer that would be the issue, especially if that's above the waterline (if it's below the waterline you'd see water leaking out).

[pepmyster]

Checked the cam, all good. Checked the strainer, even put dielectric grease on the seal for good measure.

[bud37]

If it was fine before the impeller change then the safe assumption is probably something you did. Take it all apart and recheck your assembly and hose routing. Try not to run the engine without water flow for long as you can damage the exhaust hoses.

Can you hook a shop vac on blow to your strainer and blow back out the thru hull and listen for bubbles under the boat to verify the thru hull is open and clear......good luck you will find it, it could just be an air lock.

[km1125]

OK, this might sound silly, but things do happen to the best of us. Not sure how you changed the impellers, but if you removed the pumps to do so (which I used to do on the Crusaders because it was so easy that way), then are you SURE you got the 'in' and 'out' hoses on the right ports? That could be different between the engines if they are counter-rotating pairs.

[pepmyster]

I get it. The hoses did not move from their positions since they are held together with a dual clip to make sure that doesn't happen.

[Coldcruisin]

What did the old impellers look like? Any missing vanes? Close the seacock, pull the hose from the strainer to the pump at the pump and lay it in the bilge. Open seacock and see if you get flow. Just seems like something is blocking flow.

[pepmyster]

Old impellers looked great. No missing vanes.