J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Weird one

Then you may have either a worn impeller, or a vacuum leak. Try these steps
1. Clean out the strainer and change the cover gasket. This is a common air leak source if the cover is not mated securely to the gasket.
2. Check that all hose connections are securely fastened and clamped. Make sure the hoses have not hardened with age
3. Make sure the impeller on the water pump is good and the case on the pump that the impeller mates against is not scored. It is a good idea to replace the impeller every couple of years.