IMPELLER Replacement for 2003 Air Nautigue

Hey guys, it is me again to ask about how to replace the impeller. I have had it replaced a couple of times at the shop, never done it myself. So for starters, where is the impeller located? Is it difficult to access and change?

Thanks for any help that you can offer!

Yes, the boat is a V-drive. There are two V-belts, no serpentine.

The impeller was changed in Spring 2012 by a local boat mechanic who is Correct Craft certified. He checked it this Spring and said that it did not need replaced.
However, last weekend, my 26-year old son took the boat out and came back a few minutes later as the boat was smoking and running hot.
I found that the muffler had imploded and the exhaust manifold riser was hot enough to make drops of water sizzle. I went back on the water with him and the temp gauge went up to about 200-degrees, usually reads 175. In another post, I was told that the exhaust manifold riser should not get hot enough to boil water!
Also, when accelerated to about 2000RPM, the boat would automatically throttle back down to idle, never had that happen before. I am wondering if the muffler leak which was blowing hot gases onto the electronic control box which is mounted about 6-inches away on the stern, may have caused the auto throttle downs.

Last time that I had a problem with overheating, it was the impeller gone bad, but it did not implode the muffler.

I have removed the muffler, so currently if the boat is running, it will blow exhaust inside of the engine compartment. Being as the muffler had a hole in it, I cut it out in pieces as it was difficult to access. Therefore, if the impeller is going to get replaced, I will need to do it myself, or have to tow the boat to a ramp.

I am fairly handy with mechanical work, but most of my experience has been on cars. I assume that the impeller is near the water pump, but then again it could be under the hull of the boat. That is what I am trying to figure out for starters.

Thanks for your input,

I believe most of the basic cooling system components are explained in the boat/engine manuals, available free here in the reference section. They would be a great place to start getting yourself familiarized with your boat.

The owners manual is in the reference documents, which I reviewed, but it does not give specific information like where the impeller is located! Is there a Repair Manual that is available on the website?

daletraylor wrote: Don had the boat in his shop last Spring and changed the oil etc, and wanted to change the impeller, but since I was not wanting the bill to be any higher than it was already at that point for the other things that he was doing, he said that the impeller was replaced in Spring 2012 and would probably last a while longer.

Ouch, that was an expensive decision. It would have only been like $40-50 more for the impeller if he already had the pump opened up.

I figured out how to change the impeller on a 2003 SAN with the Excalibur 330 engine, with a little help on the telephone.

First of all, the SAN is a V-drive boat. The impeller pump is at the rear of the boat on the port side, mounted near the bottom of the engine block.

Needless to say, the working quarters are very cramped, and you will be working with your head down below your body. I got a pulled muscle in my side that pained me somewhat seriously for over a week. I had to go to the doctor for medication because of it.


To access the impeller is a PITA! In my case, I removed the muffler since it was damaged and I had to take it off anyhow, but I am not sure if you could access the impeller pump without removing the muffler. Removing the muffler is a job in itself, those rubber hoses just don't want to let go.

The impeller pump has a v-belt that drives it. There is not an adjustment to the belt tension, so you have to take the pulley off of the impeller pump, which is held on with 4 bolts. The belt will come off with the pulley.

This will expose the impeller pump which is bolted onto the engine block with 2 bolts, both of which are at the top of the impeller pump assembly, which at this point will be fairly accessible.

When the 2 bolts are removed, the impeller pump can be removed from the engine and taken out of the boat to make it easier to replace the impeller.

There are 4 allen head screws that hold a metal cover in place. Once removed, the impeller can be removed. Some of the posts that I have read state that you have to be sure to put the new impeller in with the paddles in the correct direction for the roation of the pump, but I am not sure that it matters. I spun the pump in both directions and the rubber paddles would reverse direction as they are still pliable since they are new. When they are old and brittle I could see it being more of a problem.

I installed the pump in the reverse order of the above steps.

I have not tried it out yet as I am having to repair the muffler before I can test it.

Hope this helps somebody out there, I did not get info this specific to my boat when I was searching through the posts.

Dude, are you sure that you are referring to the right boat, mine is a 2003 Super Air Natigue with V-drive. The engine is in the rear, center of the hull. On both the port and starboard sides of the engine compartment are storage compartments for life jackets, etc. which have walls that separate them from the engine compartment. Even if the walls were removable, I am not sure that would improve the access to the impeller. As for a removable floor, there is not floor in the engine compartment!

Chris,
The impeller should pull straight out. They can be pretty stuck at times and the reason there's a puller made for removal. However I've never had to use one. Make sure all tip tips of the impeller aren't stuck on the housing and a couple screw drivers can be used to pry on the impeller hub. No, the cam (crescent shaped piece) does not need to come out.

How many hours are on the impeller? I'm one that feels most prematurely change them. I've gone years without replacement.

The shaft stays in the pump and the impeller slides off the shaft.