I anchored in Hurricane Bay, Fort Myers Beach last night. Very peaceful. Left early and well on the way to Naples when I noticed the temperature up to 200F. Plenty of sea room so shut down the engine to investigate.
No water out the transom. OK - start at the beginning. Turn the sea cock off - remove hose - open cock - plenty of water. Check my new raw water strainer - bit of weed but basically clean. Next, remove inlet hose to heat exchanger and run engine - water comes out but not a lot. Remove HE outlet hose - dry. OK, maybe heat exchanger blocked. Remove end caps, bend a wire coat hanger straight and rod through - bit mucky but not bad. Some tubes would not rod right through - don't know why. The spare parts manual doesn't help.
At this point the second idiot roars past within yards and the wash has me nearly out of the boat.
Run engine and still no water through heat exchanger.
Very odd.
Although water came through before the heat exchanger not a lot. Remove outlet hose from pump - run engine - no water! What! The impeller is three weeks old! Remove the cover plate making sure not to drop the tiny screws as we bounce about in the Gulf. The impeller is decimated! Only two and a half vanes left! In over 50 years of boating and engine maintenance I have never seen an impeller this damaged.
I removed the hose to the oil cooler expecting to find it filled with bits but managed to fish out just two chunks. Where is the rest?
Compared to other impellers I've come across this design seems very flimsy.
This brand new impeller lasted 105 hours in three weeks.
The vanes seem to have been nibbled away, not just sheared off.
My theory.
A bit breaks off but doesn't go down the pipe straight away but remains spinning in the impeller chipping away at the other vanes. The bits are small enough for them to pass through the heat exchangers.
Any other ideas?
After two hours bouncing about we set off again and made it to Naples and met some of the rudest boaters yet. 30kn in the harbour just feet away from me - one after another. Worse than Miami and that is saying something. Ironically there was a sheriff in his boat watching and doing sweet fa. Anchored up a creek away from the madding crowd and can't wait to get out of this hell hole.
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