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  1. #1
    Join Date
    Jun 2018
    Location
    Florida Alabama Panhandle
    Posts
    1

    Default How to ensure raw water system (pump & impeller) is wet or flooded before attempting to start?

    Hello. I got a good buy on a 6 year old Com-Pac 23D/MK IV sailboat and trailer (the "D" means the sailboat has an inboard Westerbeke 12D 2-cylinder diesel motor). I purchased the boat taking the word of the salesman and boat yard mechanic that the motor had just been de-winterized, "commissioned" and was in like new condition - plus it looks like it is in new condition. I towed the boat home and it sits in my driveway while I check things over and get it ready to sail. I want to run the motor. However, the Westerbeke owners manual and some friends all caution me not to even turn the motor over even for a second because a dry water pump impeller will self-destruct in a nano-second. One friend suggested disconnecting the raw water intake hose from the sea cock and lower a 5-gallon bucket of water down into the bilge and put the intake hose into the bucket and thus maybe be able to run the motor for a minute or two. My idea is to visit my local boat ramp one slow afternoon and not even launch the boat, but simply get it into the water deep enough to let the raw water intake have access to bay water. My question and concern is - how do I know that the water pump and impeller will get wet - have water in/around them? The boat has been sitting in my driveway and the raw water system is drained bone dry. I do not believe that simply sticking the raw water intake hose into a bucket of water or into bay water at the boat ramp will push water thru the rest of the hoses and connections and into the water pump. It seems to me, I still must run or turn the motor over for a few seconds - and thus turn the impeller while dry - to draw water into the dry system - thus destroying the impeller. I guess any new motor first put into operation would face this same problem. Or, any motor that had a water pump replaced or overhauled.
    Any suggestions on how to force raw water into and thru the water pump before attempting to start the motor?
    Thank you.

  2. #2
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    8,076

    Default Re: How to ensure raw water system (pump & impeller) is wet or flooded before attempting to start?

    Most all impeller pumps will trap enough water in their internal cavities to survive long enough to prime their inlet.

    You don't have to 'force' liquid into the intake, it will fill rapidly if the pump is ok. if you are worried about the impeller, you can pull the pump and lube the cavity....

    I'd be a bit concerned about the ramp approach....unless you plan to let the boat 'float' just off of the trailer; ie, as long at the hull is level, you should be fine.

  3. #3
    Join Date
    May 2015
    Location
    Oregon
    Posts
    134

    Default Re: How to ensure raw water system (pump & impeller) is wet or flooded before attempting to start?

    When I inspect or change impellers, I lube the inside housing, plates, shaft and key with a finger full of water proof grease. It's in the old Detroit manuals. The lube creates a tighter seal and hence a greater suction when first starting the engine along with lubing the impeller. I get very long life out of my impellers - 5 years, 2500 hours. Even then they're still good emergency spares. I inspect once or twice a year.

  4. #4
    Join Date
    May 2015
    Location
    Oregon
    Posts
    134

    Default Re: How to ensure raw water system (pump & impeller) is wet or flooded before attempting to start?

    Another thought, when starting the engine, grab the hose/plumbing of the salt water pump. After the engine starts it gets colder to the touch. I've always had walk in engine rooms and start my engines from there.

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