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Kohler 5e burning up impellers

Old 06-11-2021, 06:43 AM
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Default Kohler 5e burning up impellers

Some debris got caught in the strainer and I lost suction so i replaced the impeller just to be on the safe side. When I started the genny it was barely pumping water and the flow slowed down to a trickle, then stopped. To make a long story short I checked the sea cock. Replaced all the hoses and now the water pump itself and still cannot get the pump to pull. water. I checked and the impeller is spinning and it keeps burning impellers. I have flow to the strainer and a new hose from the strainer. I can't figure out what is keeping the pump from drawing water. I blow through the lines. My mechanic even came by to try priming tricks to no avail and we burned up another impeller last night. Again I have water flowing into the strainer, the seacock it open, all new hoses and new pump yet no flow. I am at a loss! Any suggestions would be appreciated,
Old 06-11-2021, 06:58 AM
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Look for pieces of broken impeller vanes or parts in your hose and heat exchanger,

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Old 06-11-2021, 07:18 AM
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Originally Posted by joesig View Post
Look for pieces of broken impeller vanes or parts in your hose and heat exchanger,

JoeSignorelli
Take the pump off and check it too. You may find a piece of impeller blocking the inlet or outlet.

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Old 06-12-2021, 08:44 AM
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We put new hoses and new pump in and still nothing. I get water to the strainer so now I think the strainer outlet is plugged. This all started when the strainer got plugged up. I found some greasy substance clogging the hose from the strainer to the pump so maybe it is also in the outlet??? I hope I find something because that is the only place we haven't looked. Will check it on Monday when new parts come in. Thanks for replying!
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Old 06-12-2021, 09:29 AM
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Worn pump body can cause air to circulate as impeller spins. You can test for this by taking hose off the pump and trying to blow through it. A healthy pump very little air will go through, if it breezes right through, you gots a problem pump.

Also if you suspect a strainer/through hull/sea cock problem, put a hose on outlet and blow through it, once you overcome the static head from the water outside, you will blow bubbles out the hull and will hear it.

And please no jokes about blowing on hoses!!! This is real troubleshooting!!
Old 06-12-2021, 09:33 AM
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Make sure your pump gets flooded before starting
Old 06-12-2021, 09:34 AM
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Also if new pump installed, make sure you put it on the right way!!! Rotate it 180deg and it will try to pump backwards.
Old 06-12-2021, 08:49 PM
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Thanks for your replies. I installed a new pump so it isnt that. Now that I am still having a problem I figure the old pump was probably good but at 15 years old a new wouldn't hurt. I will be doing hose blowing next time I am down there as I believe the problem is the strainer outlet. And yes the pump was installed correctly with the inlet and outlet on the bottom. Waiting for parts and will probably be on the boat Tuesday.
Old 06-13-2021, 06:36 AM
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Have you disconnected the hose just after the pump, right before it enters the heat exchanger and found no flow, or are you evaluating circulation from the discharge leaving the boat? If there isn't flow going into the heat exchanger, then you're on the right track looking at hoses/pump body.

I had a 5E with low flow and constant overheating and it turned out to be impeller chunks trapped in the heat exchanger. Cleared those out and it runs smoothly without overheating.
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Old 06-16-2021, 06:05 PM
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I had my mechanic in as I tried everything I know. He said he pulled the hose off the water pump outlet and it was sucking in. Today I tested the inlet lines and I am getting water flow to the pump so I don't understand how this could be . The new pump was installed correctly.
Old 06-16-2021, 07:24 PM
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The water need a place to go. It may not be a suction problem. Might be clogged down stream. That the outlet hose off and start the gen for 20 seconds. I bet you get very wet.
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Old 06-16-2021, 08:24 PM
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Originally Posted by fireisland1 View Post
The water need a place to go. It may not be a suction problem. Might be clogged down stream. That the outlet hose off and start the gen for 20 seconds. I bet you get very wet.
My mech said when he took the outlet hose off the pump it was sucking in. Has us really dumbfounded
Old 06-16-2021, 10:08 PM
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Originally Posted by Chilejim View Post
I had my mechanic in as I tried everything I know. He said he pulled the hose off the water pump outlet and it was sucking in. Today I tested the inlet lines and I am getting water flow to the pump so I don't understand how this could be . The new pump was installed correctly.
Inlet and outlet hoses reversed.
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Old 06-16-2021, 10:26 PM
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Originally Posted by Corndog38 View Post
Inlet and outlet hoses reversed.
This. Repeating that the pump was installed correctly won't solve the problem. Post of picture of how you have it set up op.
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Old 06-17-2021, 04:10 AM
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Suction side hose sucking flat if not reinforced or the inside of the hose could be separated.
Old 06-17-2021, 04:52 AM
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Originally Posted by tomanyboats View Post
Suction side hose sucking flat if not reinforced or the inside of the hose could be separated.

This…
Especially if the hoses are as old as your impeller. 15 Years😳
Old 06-17-2021, 07:01 AM
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If your "mechanic" found suction at the output and is "dumbfounded" you need a new mechanic.....
Old 06-17-2021, 07:06 AM
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New pump, new hoses, The problem started with the old pump so this is going on before the new pump was installed. We replaced everything thinking the pump was worn. . We put everything back the way it came out. The pump has the inlet and outlet installed on the bottom. I am in a wheelchair and can't just run down to the boat and take pictures. We tried priming the new hoses and the pump yet for some reason it won't suck water. Definitely have flow to the pump.
Old 06-17-2021, 10:25 PM
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FWIW- The specs for the 5e call for 7.6 gpm RW flow .


"I had my mechanic in as I tried everything I know. He said he pulled the hose off the water pump outlet and it was sucking in."

If the outlet is sucking in , either the pump is turning backwards rotation , or most likely as advised above, the hoses to the pump are on the wrong barbs. If inlet and outlet are both on the bottom of the pump as you indicated , that could be easy to do.
On the hoses and rw pumps on my engines I clearly mark In and out and flow arrows, especially since on my LH & RH engines the same model pumps rotate opposite direction so the hose connections are reverse of each other. I've had a mechanic attach them wrong and I had to find & fix the cause of the overheat, but now the correct way is very obvious.

All that said, if your 5e is the same as in this parts manual, it looks like the inlet and outlet are on opposite sides, not bottom . Also appears to be a crank-mounted pump. so rotation is correct but which might be easy install upside down with inlet on left side (facing it) instead of right as both Corndog and Brendanm advised..

It looks like the left side outlet fitting is straight and the right inlet may be 90* so ...maybe.... they were installed incorrectly on the new pump to cause misdirection when mounting that pump?. The old pump may have been scored and just not creating enough suction.to prime or pump.
https://manualzz.com/doc/7343658/par....3-e--tp-5987- (p. 16)

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Last edited by TTaxi; 06-17-2021 at 10:37 PM.
Old 06-17-2021, 10:51 PM
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Try and blow air into the hose, very little air will go through a healthy pump, if it breezes right through, you have a problem pump.

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