Kohler generator issue

C

cmariner32

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exMember
Joined
Jan 20, 2002
RO Number
7269
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OK, so I have changed plugs, raw water pump, oil and filter on my '89 Kohler 7.3E generator. After several minutes of running, it will shut down. As it has no computer hook-up or digital display showing reason for shutdown, how does one figure out what is shutting it down? I did notice on this latest shutdown, that the overflow tank, which is normally at 3/4 full was completely filled to the point of overflowing. The heat exchanger felt hot several minutes after shut down, but the exhaust hose felt cool-not sure if the heat exhanger tempt was the situation at shutdown. Any troubleshooting tips are very much appreciated. I'd sure hate to spend the bucks to have a generator tech come out to tell me something that I could have figgered out on my own (with a little help)
 
Get an IR thermometer and check coolant temp at the Tstat housing and the temp sender. That will tell you if it is shutting down for a valid reason (running hot)

If temp is ok, temporarily bypass the temp switch while monitoring temp to see if it is defective
 
If it shows excess temp, are you observing what looks like noramls water flow with the exhaust? Without steam? Does it sound louder? Perhaps take a dip and check for a bag or weed clogging the RW intake, or try backflushing the cooling system?
 
As Sandy suggested, start at the beginning of the raw water cooling system and work your way down stream. Make sure you have good flow of raw cooling water into and out of the engine first. Only then start looking at the fresh water cooling system and high temp. shut down sensor.

And just a thought, after you changed the raw water pump did you open remember to the seacock? :-)
 
Sandy/Capt. Bill-my water flow out the discharge is 3 times the volume that it was previously before the water pump changeout-the old plastic waterpump only had 2 full impellor blades-I had to pick out the missing pieces from the hose and fitting at the heat exchanger, I'm pretty sure I got all the pieces-so water flow is not the issue. The temp of the discharge water was pretty warm-perhaps 120 degrees, but I don't know what normal temp should be-there is no steaming. Pascal, your suggestion about checking the temps at the t-stat housing will be my next check. Do you have any idea what the normal temp should be? Thanks to all for the help.
 
can you see exhaust water exiting the boat?? Did you find all the pieces of the old water pump?? did you open the seacock?
 
Not sure about your model Kolher but I know the 5 kw had problems with air getting trapped in the closed cooling system and causing local overheating problems, triggering a a over temp shut down.
 
There is a plug on the opposite side of the anti-freeze cap when fill up with antifreeze remove the plug till antifreeze comes out put the plug back and after adjust on the cap.
 
Is it a cooling problem....install a $30 water temp gague.
After "shutdown", does it immediately crank and spark???
The shutdown switches (LOP, HWT, HCHT)connect together and go the the terminal board in the Controller. To isolate switches out of the circuit, disconnect the wire and test restart.
 
one of your sensors, water or oil pressure is going to ground, thus turning off the motor. My bet in on water temp, pull the lead wire off the water sensor and see if it runs, if it does your problem is with the cooling. How much water are you
pumping overboard, is it the normal amount? I have had the water pump impeller cam wear down, ususally after about 1500 hours, its hard to see the wear down is so slight, but it will reduce water flow. How much time is on the water pump?
 
I believe I got all of the impellor bits out of the unit. The outflow of cooling water is much greater than what it was before I changed out the raw water pumpt due to a crack in the original plastic pump, however, I had the shutdown problem even before the water pump change-out. I suspect the problem may be the water temp shutdown due to the overflow resevoir filling up after the shutdown. Assuming it is and it is not the raw water cooling side causing the problem (the exhaust hose temp was normal and the exhaust water temp was warm-to-hot), where do I go from here? Do these engines (Kawasaki I think) have a circulating pump and T-stat too? I am a total newbie with these new-fangled 24 yr. old generators-but my learning curve is quick. Thanks to all for any information.
 
As two others have suggested, it sounds like you may have an air lock. Look for the fitting boatcomfort described or you may have to drill one out.

Billy K.
 
It ran for upto an hour or so prior to my latest upgrades. If it was an airlock, would it not shut down sooner than that? The latest shutdown occurred perhaps 15 minutes after running with a load.
 
You need to get a heat gun so you know if it really is running hot some where in the system or if the sensor is acting up. They do have a thermostat and circulation pump.
 
Which model Kohler do you have a 7.3E? It's possible the raw water side has built up internal scaling. If this is the case you might have to circulate some Barnacle Buster through the raw water side. I had something similar in my 7.3ECD last summer. My unit was only 5 years old and the electronic version (7.3ECD).
Bill
 
Great info Prince....TYVM. The operating manual that came with the boat is sadly lacking. I do have a IR thermometer and my next check will be monitoring the temps until shutdown. The coolant recovery tank filling up during my last startup was my first clue that the problem may be temperature related. The boat spent most of its life in fresh water, which I'm finding out the hard (and expensive) way, does now seem to negate the replacement or cleaning of raw water cooled devices.
 
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