FORUM RULES UPDATED - The forum rules have been updated to continue to provide a friendly and safe environment for our member community. Please take a moment to review the updated rules and our terms of use and privacy policy. Click here for Forum Rules which has links to the 'terms of use' and 'privacy policy'.
If the engine has been run previously, there is still a residual amount of water in the pump chamber that acts enough as a lubricant for the few seconds that the water takes to reach the sea water pump. If the impeller has just been changed/inspected, then it is a good idea to have liquid soap as a lubricant (usually needed to install the impeller.