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jeffk

Kohler Generator 5EKD

10 posts in this topic

Has anybody had this problem, I keep spinning the hubs on the impellors.

While it is not a big cost to replace, it should not keep happening.

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Are the blades all facing the same way? Are the facing the right way? Are you lubing the housing when installing?

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Everything is installed correctly.

My impellors last about a month than the hub spins.

 

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These pumps are of a positive displacement design and when in motion, they must move some amount of water or they will self destruct as there is no pressure relief system built into the piping network. As such, when the thermostat is closed, the raw water remains in closed loop circulation, virtually deadheading the make-up sea water pump. To maintain minimum flow to both cool the impeller, and prevent an over-pressure situation, a bleed hole network allows a slip stream of water to both by-pass the thermostat and cool the engine exhaust and it sure sounds like this passage is partially blocked. There is always the possibility that the suction piping/strainer is restricted that would reduce net positive suction head pressure, putting the pump into suction cavitation too, which is also really hard on the pump internals. Impellers should last for multiple seasons under normal circumstances, and the first thing I would do is measure the amount of water being discharged overboard upon initial start-up, as compared to how much water is being delivered at the actual pump discharge. I feel you have a flow restriction somewhere. One last possibility is that your pump housing is not machined properly, and too little end clearance is pre-loading the impeller to the pump case causing excessive drag during operation. Careful measurement should tell that story. Is it square, and do you have to drag the cover plate on with the retaining screws.  W. 

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4 hours ago, Wingnut said:

Impellers should last for multiple seasons under normal circumstances,  W. 

I don't know about that multiple seasons, I am really lucky if the impeller last one season.  Not a big deal. Just replace it in the spring before the season starts.

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The the genny ran perfectly today.

Until I shut it down, waited two hours and will not restart.

I know nothing about these units and really have no time, calling in a kohler repair tech

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On 9/23/2017 at 0:54 PM, mpm330 said:

I don't know about that multiple seasons, I am really lucky if the impeller last one season.  Not a big deal. Just replace it in the spring before the season starts.

A few questions. Was yours a factory install? Do you clean your suction strainer regularly? Do you seek out a fresh OEM replacement impeller, or do you use aftermarket? How fast does you pump establish prime upon initial start-up? Upon winter lay-up, are you using quality marine RV anti-freeze?  W

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1 hour ago, Wingnut said:

A few questions. Was yours a factory install? Do you clean your suction strainer regularly? Do you seek out a fresh OEM replacement impeller, or do you use aftermarket? How fast does you pump establish prime upon initial start-up? Upon winter lay-up, are you using quality marine RV anti-freeze?  W

Yes, factory install. Clean strainer several times a year. Yes, impellers are OEM. Not sure on how fast it establishes a prime, but by the time I go from cabin to the rear of the boat it is pumping water out the side. There is no winter lay-up, so no anti-freeze. 

I do find that the impellers last longer if I limit the amount of cruising I do with the gen running. It is not something I worry about, change in the spring and keep a spare.

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Sounds reasonable, as season is much shorter here, and few summer days are so oppressive that owners see the need to run the Gen set while underway. Fresh water area too. Neighbor has a 40' sail boat and he uses his gen set a ton and gets 5 years out of his impeller without failure, but the pump is quite large and turns slower as his gen-set is a diesel. Underway speed is pretty slow also as you can imagine. The raw water inlet is really deep on that hull providing higher net positive suction head pressure and fast prime. My install on a 30' Sea Ray (10 KW Onan) would lose prime while underway until I changed the thru-hull inlet scupper to more of a scoop design., I know something about Texas summers, as I spent many a July at the Beaumont Refinery, sister lives in La Marque, and best friend resides in Sugarland. Stay cool...  W

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When my gen works it cools down the cabin pretty quick.

I do not use it when running.

I called a kohler service tech and got put on a list......and its long!

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