4K military not putting out much.

I got this old military Kohler with a K331 EP engine as a hand me down a few months ago. Today I was trying to find a good spot under a shed roof to set it up as a backup generator.

All I checked before was the 110V outlet with a Killawatt meter and the cycles was 59-61, and the volts was 119-122VAC. Pretty good I thought since the electric start works and the single plug engine runs very smooth.

Today I hook the unit up to my barn and was hoping for a connect back to our outside kitchen just in case. In my barn I have a 220 AC unit I tried to test it with the old generator, but the AC unit had trouble getting enough juice to run properly.

Testing the AC while the unit struggled I saw the voltage was down on each side to less than 50vac. The fan would run but not the compressor.


With nothing plugged in the 220 plug is a good 119v on each side and the single double outlet has 199 in each outlet, but the 220 AC fails or pulls too much.


Everything 110Vac works great but not the 220 trying to run a 220 AC unit.

110 heaters, hairdryers, fans, drills all work great but not the 220 device.


I have two other portable generators but I've never hooked up the 220 side before , only the 110 side when we lost power.


I was hoping to run the entire outside kitchen which includes two 110 ac units, one Fridge, and lights. I know the other generator would do the job but I can't leave them outside like the military because it's enclosed.

Any idea on the low 220 side during connection to 220 AC?

Assuming the 4K means 4000 watts, the maximum output in amps at 240V is 16.5A. 1 - Wire between generator and connection is too small, smallest wire size should be 12awg, larger for longer runs. 2 - The AC draws more power than this unit can handle, check the plate on the AC unit. An AC unit will require some surge when first starting.

ACs are beasts at startup... definitely look it over, and determine what the start up draw is. You certainly might have enough power for continual run... but if she can't start?

I created a 220v pigtail using a dryer cable and placed two outlets, one on one side and one on the other side of the 220 pigtail.

I connected a 8000btu 110 AC, two blowers and a 110 heater on each side of the 220v pigtail and they all ran great. I plug in 1 220vAC unit to the 220v plug and the 220v AC fan works but not the compressor.

I tried reversing the 220v poles and get the same results.

The old girl will run several 110 heaters or AC units but not one 220vAC by itself.

Could it be the old girl is just tired? Will, by running the generator, for hours help the output. Will running a generator that was little used help bring it back to life.
Can you run the crud, lacking a better word, away or will running a unit help clean the contacts?

Please supply us with some details about this air conditioning unit, including capacity (tons) and the current rating. I've come across motors that when starting, actually draw 10 times the running current briefly, as measured with a high quality meter with a peak-hold feature. My MEP-003A, rated at 10 kW, sounds quite maxed out when starting my industrial 5 hp air compressor. That motor is rated at 24 amps at 240 volts, which would seem to require only 1/2 the capability of the generator, bit almost certainly exceeds its 52 amp rating when starting.

Triple Jim said:

Please supply us with some details about this air conditioning unit, including capacity (tons) and the current rating. I've come across motors that when starting, actually draw 10 times the running current briefly, as measured with a high quality meter with a peak-hold feature. My MEP-003A, rated at 10 kW, sounds quite maxed out when starting my industrial 5 hp air compressor. That motor is rated at 24 amps at 240 volts, which would seem to require only 1/2 the capability of the generator, bit almost certainly exceeds its 52 amp rating when starting.

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I agree 100%. Also does the AC work on utility power. Also are you running off utility power then immediately unplug and connect to generator, needs to sit 10 - 15 minutes for the pressure to equalize. We do need to know the name plate Specs.

I cannot easily get to the AC unit. I built it in high in my barn and sealed it up including the front panel. I can pull up and out to clean the filter but that's all But even that requires moving a bunch of heavy stuff first.
I was hoping to use the military generator to run the 220 barn AC off and on in the hot summer time to keep it up and to cool the shop.
My idea with the old generator was to run the outside kitchen which has a bath and bedroom during power outages. The little house has another smaller 220AC unit in the living room. That 220AC is only 10 years old. The 220AC in the barn is probably 25+ years old and may take more juice than the old girl can give on startup.
Both 220 units run great on local power when plugged in. I keep everything unplugged when not in use.

I'm going to have to wait until I can convert a 20' 30amp RV extension cord to house power with 220 dryer cable adapters that arrive next week. We live in the country and order most items online.
We go to the city about once in 10 days. Most stuff I order is from Texas so it arrives in three days and I don't have to get out.
Thanks for your help.

If you can't get to the name plate can you get your multimeter on the line power and see how many amps the barn ac draws on start up?

Or at least the running current if you don't have "peak-hold" on your clamp-on meter, since starting current comes and goes very quickly

I'll try to get a current reading tomorrow. Today I spent the day adding another breaker box below the meter base at the little house. I needed a way to shut off the power company from the barn and house. I now only have the 100amp breaker in the box below the meter feeding the barn and house.

This way I can turn off the power company and turn on the generator. I should be finished by tomorrow night. Tree trimmers coming out tomorrow to clean out the property power lines Not related to what I'm doing.

Also if I'm lucky I'll know if the old generator can run a almost new 220 AC unit that's inside the little house.

No luck guys on the 220v ACs.

I made all my connections yesterday and ran the old military generator for over an hour supplying power to our little house we call our outside kitchen.
The old girl will not run the 220v AC in the living room either. It just doesn't have enough power.

But the good new is it will run all the lights, the dishwasher, the fridge, the 110v AC unit in the bedroom, the 2nd 110AC unit in the pantry next to the living room, and run the power in the barn all at the same time.

I was hoping to use the 220v AC but I'm OK with what it will run.

Now my next test is to see how long it will run on a gallon of gas. My portable generator that I can't leave out I the open, will run for 8 hours at 5 gallon of gas.
This old military unit has a smooth, low rumble exhaust. The other unit is loud and we hope the old generator will serve our needs. The longest generator run we have had here in South Louisiana was 8 days with out power company service.

It looks like at this time today the hurricane in the gulf will miss our area. We live 75 miles west of Baton Rouge, 75 miles east of Lake Charles near Lafayette Louisiana.

Glad the hurricane missed you. Now I will never know how many amps your 220v air conditioner draws. How many btus were each 110v air conditioning unit ?

I believe both 110vAC units are 6kbtu. I can't pull the amps on the 220vAC units because I prewired all the outlets so I can't isolate a wire to use the clamp meter.

I expected more out of the old military but I'm OK with what she does put out. When we built the little house it was the first dwelling built here for a hundred years. We have 8 acres but only cleared about a half acre to live on, the rest is a natural forest undisturbed by man for those 100 years. I had met the mother and father of a friend that died several years back but I didn't know he was born next to my land in a shack down by the bayou.

The rest of hurricane Nate is now in Tennessee I think. We missed the first two big gulf hurricanes so I expected Nate to hit us this time. I guess there was enough prays said down here to keep it away. Sorry to those that it did visit.

I was finishing up closing the electrical panels and saw my chance to take a clamp meter reading in the fuse box. I had the clamp meter on and attached and turned on the old 220V Ac in the barn. By the time I got back up the ladder the amp reading was 14.5. I'm not able to get a startup reading since I need a ladder to turn the AC on and another to check the meter. I have two ladders but I can't be at both places at the same time.

14.5 amps 10 seconds after startup.

The old AC will cool the barn in less than 10 minutes since it's insulated, but I prefer to open the doors on most days for a breeze.

The peak is likely to be at least five times the running current, from measurements I've done.

Just turn the AC unit on and hurry down the ladder to get the reading as it starts. Like jumping in bed before the light goes out ...

TheBishop said:

14.5 amps 10 seconds after startup.

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That is a bit much for a 4kw generator to start.