Changing Your Impeller

The following article is how to change an impeller on a 2001 Tigé 2300 V with a MerCruiser 350 Mag engine. Other Tigé V-drive models may be similar. If you have a Direct Drive model you may pick up some useful tips, but the procedure for removing the pump will not apply.


**** Disclaimer: The following instructions are provided as a guide only. By following the instructions in this article, you are doing so at your own risk. TigéOwners.com, Tigé and the author of this article will not be held responsible for any damage that may occur to you or your boat as a result of the steps below.

 

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Publish Date: 7/28/04
Published by: RZMike
Time Required: Less than 2 hours
What you will need:
  1. S.A.E. Socket set
  2. S.A.E. Combination Box/open-end wrenches
  3. Flat head screwdriver
  4. Impeller (available at Overtons.com)
Resources/Suggestions: - I like to use www.mercurypartsexpress.com to order MerCruiser parts. I don’t have a dealer nearby, so they are more convenient. Even if you don’t order from them, they have a great parts lookup with diagrams. All you need is your motor’s serial number.

- Mercruiser Service Manual. Always a good thing to have. It’s large. I had to buy a 3 inch three ring binder for it.

- TigeOwners.com Forums. If you need help, there’s a lot of knowledgeable guys there as well as Tige dealers.

Click thumbnail for a larger view.

Step 1 The seawater pump is located on the port side of the motor at the rear of the boat. Here's what you'll see after you pull the port engine panel out. You can just see the pump behind the fuel filter (blue arrow).
 
Step 2 Remove the belt by first backing off the locknut (blue arrow) and then turning the smaller bolt (red arrow) On my particular model V-drive engine this pulley is located on the port side above the pump. It may be in different locations on other models.
 
Step 3 Remove the fuel filter from its bracket and pull it out of the way. Loosen the hose clamps (blue arrows). It’s a good idea to take note of which hose goes to which outlet. My outlets were marked – yours may not be if the housing has been replaced with an aftermarket item.
 
Step 4 Remove the two bolts holding pump bracket to motor block. The pump is now free. Removing the pump from the engine compartment may take some maneuvering of the pump and the fuel filter. As you pull the pump towards the back of the boat the hoses should pull off the back of the pump. If the hoses seem stuck, it may help to gently pry the hoses a little to get them loose.
 
Step 5 Alternate View of Components
Here’s an alternate view looking straight down from above just in case you having trouble locating something.

  • Blue Arrow - pump bracket bolts.
  • Yellow Arrow - Pump.
  • Green Arrow – Hose clamp
  • Red Arrows - Nuts to remove fuel filter and bracket
 
Step6 Once you have the pump out and on your bench, make a note of the bolt and nut locations for reassembly. Three of the bolts just hold the impeller housing to the shaft/pulley assembly. The other two (red arrows) hold the housing and also secure the bracket on the pulley side with nuts. If you ignore or forget this step, it can be confusing when trying to reinstall the pump as the bracket will go back on in several different positions.
 
Step7

Here’s what you can expect to find when the pump housing is removed. Once you clean out the impeller pieces, check the impeller housing carefully - it is usually plastic. If there is any damage such as scoring, it should be replaced. There are also two o-rings. The first you can see on the impeller housing (blue arrow). The second is a small o-ring on the shaft, beneath the thin steel plate. I didn’t remove the plate for this picture, but the yellow arrow shows the approximate location.

An important consideration is the location of all the old pieces. Sometimes chunks of the impeller can get caught in your cooling system and cause a blockage. First time out after replacing the impeller, always keep an eye on the temperature gauge to make sure there aren’t any problems.

When inserting the new impeller, it’s easier if you use a little lubricant. I used some marine grease, but silicone spray or even binding lube will work.. It’s a tight fit and you will have to bend the impeller vanes. Just try to bend them to follow the direction of rotation. On my pump the rotation was marked on the housing. If you happen to get the vanes backwards they are flexible and should flip over when the motor is cranked.

Reverse these steps to reinstall the pump. Double check all your nuts, bolts, and clamps.