How to Change Impellers in 8.1's with Pictures

Water may start to come in unless you keep the hose up high but I would get a piece of dowel to stick in the hose (not sure the diameter) just in case. Since water seeks its own level and the B3 pickup is low you may be OK.
 
John, great post! I just used your document to complete my impeller replacement on the starboard engine and my first time at it, completed in an hour and 15 minutes. priming via the top blue stopcock is very important! Also I didn't have to remove the temp sensor or fuel filter, it made it a little more difficult but not that bad. I found using vaseline makes things go back together much more easy as well as installing the impeller and the water hoses, use a pair of channel locks to grab the hoses and gently push them back into place while pushing and wiggling the pump back and forth to get the hoses to seat.

Bill
 
Thanks so much for this informative thread. I just did the starboard pump to get the boat running again. I'll save the port for a cooler day.


At at some point, sea ray installed a belt tensioner (mine's a 2005). It made that part a lot easier once I figured out I didn't need to move the alternator.
 
As someone who is getting ready to tackle this process in the spring thank you for saving me on labor. There is a standing drink offer in the DC area should you like to claim it.
 
Do NOT use Vaseline on Rubber or Plastic as it will weaken it causing premature failure. Only use rubber safe silicone grease or just soapy water.
Here is a rubber and plastic safe silicone grease: Super Lube 92003 Silicone Lubricating Grease http://amzn.com/B0081JE0OO
 
Great pics and instructions. I did my 2006 Sundancer with 8.1's today. I think I had a slightly newer version of the engine that what was depicted, the differences were:
- Had flywheel belt tensioner, not the bolt type off the alternator, this was very easy to remove belt.....just crank the tensioner and slip the belt off.
- Instead of a clip on the water pressure sensor I had two separate tubes (very small one green and one white) they look like wires, but the are hollow tubes coming off the pressure sensor. You will also see a black tube, it's just a vacuum hose and not attached to anything, remove the pump with the black hose on it, it's 12" and not attached to anything.

Everything else was basically the same, you will have to remove an idler wheel to get to the top bolt on the bracket, it's easy, you'll see what I mean. Also my hoses we very easy to remove and the boat had not had it's impeller changed since purchased (190hrs). All in all it took me an hour to do the port engine (w/o removing any exhaust hoses) and a helper topside to hand tools down.

When opening the blue petcocks to prime the pump I did not get any water to gravity flow through, so I had to remove the water intake hose from the strainer and fill with water then reattach to strainer. That primed the pump.
 
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This was such a great tutorial, it's a shame to lose the pictures. So, I've upload the entire post as a pdf here with the original pictures:

Download PDF: How to Change Impellers in 8.1's with Pictures.pdf
http://s000.tinyupload.com/?file_id=02697398712122697579
PDF Attached: I've also uploaded the file and attached it to this post (see "Attached Files" below).
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1) Close Sea Cocks.

2) Remove Serpentine Belt: Note free play, then loosen alternator tensioning assembly as follows: Loosen the nut nearest the center of the engine and spin it over about and inch. Loosen the bolt at the end about an inch and allow the alternator to swing inward to loosen tension on the belt. If it doesn't swing, loosen the bolt that acts as a hinge at the top of the alt. Swing alt in and slide belt toward you off of one of the pulleys that doesn't have ridges. Keep track of direction of belt by laying it down without turning it over.

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Once the belt is off, remove the 2 nuts and 1 bolt that hold the pulley bracket and raw water pump (impeller pump). The bottom 2 are of one size, are nuts, and secure the pump. The top one is a bolt of a slightly different size and only holds the pulley bracket.

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Remove the pulley bracket and 2 pulleys and set aside.

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Reach behind the port side of the pump and remove the two, blue plastic wing-bolt style plugs and set aside. Keep track of the O-rings. Remove the two hose brackets off of the two hoses. The bottom is outgoing and is somewhat plyable. The top one is red and is the incoming, vacuum hose (withstands vacuum from the pump). It is short and not very plyable. Remove the wire harness to the sensor from the back of the pump. There is a small tab which extends the entire length of the black plastic housing. Lift the tab and separate the two halves of the sensor housing to free the wiring. It is a lift tab.

Try to work the hoses loose by the least aggressive method possible. Try using your hands, then perhaps and awl, and in the worst case, a big ass screwdriver like me.

008.jpg


Once the hoses are loosened up, the pump should, theoretically, pull off straight. In reality, it won't. Put your right hand behind the top, right side of the pump and begin to pull it off of the bolts and away from the hoses. Work it up and down and back and forth. As you begin to get it out away from the block, put a large socket piece between the pump and the block from the top right to hold them apart at the top. Then, pull the pulley (bottom of pump) away working side to side. Finally, give up on brut force and work a large screwdriver between the left side of the pump and the block. Make sure you do not put any pressure on any fuel lines, sensors, or other sensitive parts. Pry the pump free of the hoses.

009.jpg


Remove the 10mm nuts from the back of the pump. There are 3 lengths. 2 long ones hold the bracket. Several short ones hold the pump together. 1 medium one holds the base of the bracket to the side of the pump. Don't forget this one.

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Lay pump on pulley and remove other half. Observe rotation of Impeller.

011.jpg


Check for wear of the housing. If it's worn, replace it - the labor is the hard part, not the cost of an entire pump.

012.jpg


Take the impeller out. I used to flat screwdrivers on opposite sides prying it out at the same time. Set it down in the same position to reference spin direction. Begin to insert new impeller while bending vanes over as you go around the circumference to get it started into the pump. Once you get it started, spin the pump using the pulley as a base plate and push down on the impeller to get it to go in. (I didn't notice until I got home that in the video below the pulley was slipping on the towel so you can't see the rotation of the impeller, but you get the idea.) Lube the impeller with soap or something.



Put the new O-ring into the slot. I "Glued" mine in 2 1/2 years ago with grease to get it to stay. It showed zero wear. This time, I just held it in place while slowly sliding the other half of the pump in place to keep the O-ring from coming out of the groove. Once I had it in place, I looked around the side of the pump to make sure it matched perfectly to ensure the O-ring wasn't crimped. Put your favorite product on the bolts and replace them. Put your favorite product on the hose nipples to make them come off next time. Push pump back in place while aligning hoses. Bolt on with pulley bracket in place. Replace hose clamps carefully - in place and straight. Replace sensor wiring plug. Replace blue, plastic wing bolts.

Put serpentine belt back on the way it came off, sliding it on over a smooth pulley as the last part. Use other engine or guide sticker on engine as a guide. Re-tighten the bolt on the end. Re-tighten the securing nut. Re-tighten the hinge bolt (I still have to do that on the port side - I forgot). Tighten the alternator adjustment until you can just displace the longest stretch of the belt 1/4" with pressure from your thumb.

For port engine in a 2003 1/2 - 2008 340DA, move the muffler out of the way. Remove 4 base screws. Remove a couple of the exhaust hoses strategically to allow the unit to be moved aft without taking it all apart.

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OPEN THE THROUGH HULLS!

Then, loosen one of the Blue Plastic Wing Bolt Plugs until water flows out to prime the lines. If you open the "Out" side port (where water flows out of the pump) and get some water, then the pump should be primed and good to go. If no water comes to that one, then open the other to get very close to a good prime. Shut those also.


Today, this took a total of 3 hours for both engines. Total cost - less than $100.
 

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Great write up.

I have Mercruiser 454s, but Crusader bronze pumps. Sherwood’s actually.

When changing the impellers last year I found some scoring on the side surfaces as well as cracked carbon bushings.

I measured the depth of the bushing bores and the length of the shafts that would go into them to decide if I had room to remove the scoring from at least one side of the pumps and I did.

After the new bushings were pressed in, I lapped the cover plates flat making sure to preserve that depth.

So far, so good. The pumps move tons of water and cooling seems fine.
 
Glad to see the pictures are back on the original post. My pdf above is handy to save on your phone or laptop in case you ever need it while away without internet.
 
Glad to see this old post still survives. Ran thru these instructions Saturday they are 100% legit and correct, but I believe a little more emphasis should be placed on the "priming" of the raw water to the pump. I opened the blue plastic drains but probably not long enough to allow all the air to flow out of the top drain hole and did not get any water on my first two attempts. (Luckily I did use some thin silicone grease to lube the vanes before closing the pump so I was not TOO worried about burning the impeller.)

After going back to the boat and allowing about a gallon or so water to flow thru the inlet side pump drain, water started flowing thru the pump. Also when pulling the pump, the entire raw water side drains down as well, taking a much longer time than usual for water to start flowing out with the exhaust.

Might also want to mention about locating any missing impeller vanes, found mine in the transmission cooler inlet:

44012951081_a784d445fd_z.jpg
 
I changed my first 8.1S impeller following this extraordinary post. Thanks a lot Hampton!;)
 
All, any feedback on completing this operation on 2004 340DA with V Drives? It looks like I will be laying on top of the motors to get to the water pump
IMG_1563.JPG
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When I did them on my 2002 the Starbord was easy, the port was horrible to try and get the lower hose back on..... I had one guy laying on the rudder pushing and one guy doing the hose clamp from beside the motor and the black water tank
 
All, any feedback on completing this operation on 2004 340DA with V Drives? It looks like I will be laying on top of the motors to get to the water pump

I did my 2004 2 years ago.... Hampton's post is spot on.... get the port side muffler out of the way
 
I did mine last April. After removing the port muffler I had space to do both pumps from the front of each engine. I used a little of silicone grease on all hoses. I broke one of the blue plugs removing the port pump. Next time I'll remove the plugs before working on the pumps. The hardest part was removing the clamps from the back hoses.
 
There is actually a good amount of room behind that engines once you are back there and have the muffler out of the way.

It would be helpful to have you tools down there or at least a helper to pass them down.

-Kevin
 
Removing the mufflers seems like more work then its worth... as my issues where below the stringers at the bottom hoese not the main bolts on the pumps.

I tried to get the exhaust hoses off an they where STUCK felt like I would break the fiberglass elbows or muffler
 
Port side pump is really difficult to remove with the muffler in place. But not imposible. Starboard side can be done but you will have more room with the muffler out. The main problem is to reach and see around the stringers as you mention. But after you take the muffler out of the way you can reach behind the pump from the side and the front of the engine.

To remove the muffler drain the water first. Spray some penetrant oil around the houses. Then wiggle the muffler up and down until it comes lose. You won't brake the elbows. Be a little bit careful with the muffler, but most likely you'll brake the hoses before anything else. It looks like a lot of work. I didn't want to do it first. But it didn't take much to remove the muffler and there was so much more space to place myself while doing the job.
 

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