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Sherky

Impeller service

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Looking to possibly do some maintenance items myself this year.  Boat gets a new impeller every other year at the dealer.  Generator is now due for an impeller and curious how difficult it is to replace.  Looking for a good video but haven't found it on the Kohler 5e.  Thanks!

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This is a super easy DIY task. If your boat is in the water, just be sure to close the seacock!  I do mine myself every year....takes about 10 minutes.  The only challenge on some boats is access.  I have a Kohler 7.3, but I just remove 4 bolts on the front of the impeller housing, pull the housing off, remove the old impeller, replace & reassemble. 

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+1 on the ease.  I have the 5e also with a sound shield.

I expect yours is mounted similar to mine (with or without the sound shield).  The impeller is on the starboard side of the generator/boat.  I have to take off the front sound shield cover and then a couple of screws on the starboard side (easy to see and do) to remove the shield on the starboard side of the generator (but I have to lean across the top to get to that side.

As Mrcody says, close the seacock.  Then remove the four small screws/bolts that hold the housing and cover on.  Mine also has a spring on the impeller shaft that I have to watch for, but it's not under a lot of tension.  If there are any vanes missing from the old impeller, I take off the hoses on the housing and disconnect their other end and check for loose rubber pieces.  I've never had an issue with anything getting stuck way up in the cooling system or the heat exchanger/muffler.  Housing comes off and the impeller is either in the housing or stays on the shaft.  When you take the old one out, it's a good idea to remember which way the vanes are compressed and install the new one so it looks the same.  If you miss it, it's still pretty easy to figure out, since the little pump housing inside is not a true circle, concentric with the shaft hole.  You can see where one wall of the housing is closer to the shaft just next to the exit port.  This is where the vanes are compressed to create pressure on the water and force it out of the exit port.

I also check inside the housing for any sharp edges, burrs, etc., which might wear on the vanes.  I use glycerin on everything to lube it up for first rotations.  I get the glycerin at Wahlgreens or CVS in little plastic tubes (used for enemas, but nobody looks at me funny, even when I buy in bulk).

Put the new one on, install the little, thin, o-ring gasket, and press the housing against the spring that's at the base of the shaft, install the bolts, check all hoses for proper clamps.

OPEN THE SEACOCK!!!.  Check for leaks after the seacock is open.  Then run it and check for leaks during operation and make sure lots of water is exiting the exhaust port.

Put the sound shields back on. 

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+1 on being an easy fix.  

I'd also recommend keeping a spare on board, since it IS an easy fix and can be done on the water if necessary.  I had my impeller go out in 115 degree heat in the desert...didn't get to run the a/c during the day so we lived in the water.  Luckily we had hook ups at the dock for night a/c.

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Thanks for all the replies.  I took a shot at it last weekend and got it done.  The hardest part was knowing whether the new impeller was pushed in far enough.  Got it all put back together and ran the generator hard for a couple days on our lake trip.  Ran great. 

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Some people are saying the plastic impellers are a newer PPS plastic, and they're better than the original ones. The new plastic ones last a long time and people no longer have issues. Others say that metal is the only way to go and that they don't fail. Then I research metal ones, and I read all this info about the bearings in them failing because the metal impeller is heavier.

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Please share your research link on metal impellers. No one else has ever heard of such a thing. Plastic either for that matter.  Carbon reinforced EPDM rubber is the norm.

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The hardest part for me was getting the new impeller on.  A buddy said to wrap it with dental floss to compress the splines.   Worked like a champ.   Just member to unwind the floss after you put it in..  

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