Hi
Yep no one wants to do this job in the boat! It is much easier when the engine is on a stand! Beside you have plenty of money if you have a boat!
Just pay the big bucks!
However .....
It can be done without pulling the engine! You need the correct tools and you better be a skinny dude! You are going to have to remove the engine hatch for access and many other engine parts to get to the pump! It can be done in the water if you know what to do and have the correct fittings and hose! The trick with the hoses is to have a 2 foot piece of hose with a bared fitting once you loosen the hose to the sea water pump the water is going to come in! Not to worry about a few gallons of water fit the 2 foot hose with the barbed end into the hose you disconnected, raise the other end above the water line of the boat, presto the water stops coming in! As long as the open end is above the water line of the boat, no water can come in! Be prepared to do the same for the other line! Now you are going to have to remove a bunch of stuff off the engine to get to the raw water pump!
It helps to have all the correct tools flex joints and extensions are what you need several different lengths and several flex joints will make the job easier! If you can find one, a 3/8 drive flex cable drive about 20" long makes the job easier! Don't forget about a magnet on a flexible 3 foot handle to fish out the bolts you are going to drop in the bilge under the engine!
You will need a mirror as said or a small camera and a monitor! I use a small IR camera on a threaded rod wired to a 20" flat screen to see! My camera is only a 1" in diameter and 2" long mounted on a 3 foot 1/4" steel threaded rod! This allows me to set the camera in place and have my hands free! The base is a magnetic machinist base for dial indicator, since it is magnetic I just attach it to something metal and set the camera up! Sounds like allot but I had this stuff just laying around!
Now you are going to completely remove the pump as you will not be able to remove the impeller any other way! Once you get the pump in your lap it is easy! First when you take the pump apart do it in a well lite area on a table! Once you get the pump open look at the old impeller note the direction of the bent blades as the new one needs to bend in the same direction! As AL said go for the neopreme impeller they last longer and wear better, they do cost more! Now when you get the old impeller out check to see if you can find all the pieces any missing pieces need to be looked for as they can plug up small water passages that can cause the engine to over heat! Put some grease on the new impeller and inside the housing! Take the new impeller and push and twist it at the same time in the direction so the blades are bent in the same direction as the old one! Clean off any mating surfaces and replace the seals! Be careful when tightening the screws back up as they break easy and you will not have a good seal! Remember the impeller type pump is what is called a positive displacement pump! What goes in must come out it needs water to stay cool but it is just as happy to pump air until it melts! A proper seal is required!
Now just put the pump back on the engine attach the hoses check for leaks! No leaks put every thing back together the way it came apart! Your ready to go!
Now the one thing I can not say enough, if you are a husky dude, this job is going to almost impossible! You are going to spent allot of time with your head lower than your butt!
It does help if you got a skinny 12 year old boy to help out or borrow one from your neighbor! $50 goes along way for a kid! Cheaper than $2000 and pulling the boat out of the water!
Good luck!
Mike -
