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Frequently Asked Kohler Questions


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Folks!!, When you ask our Resident Smart Guys for help, Please give us ALL the information you can. Saying you have a "Kohler Genset" just in NOT enough for us to give any reasonable advice. What we NEED is complete MODEL and Serial Numbers, and the best description that you can give of the problem at hand. Pictures are also VERY helpful in determining Models and Options.


The really critical number on any Kohler engine or generator is the spec number. All parts, production and electrical data is tied to spec number.

Also, when checking numbers on a generator powered with a Kohler engine, be sure you're getting the generator data,not the engine. Both data tags will be present, but they very clearly marked as "Kohler Engines" or "Kohler Generators."



Re: Frequently Asked Kohler Questions - Kohler Generator Manuals

I thought this might be helpful in the FAQs, since it's a question that comes up quite often in this section of the Stax:

From their inception in the late 1920s until the early 1970s, Kohler Generator Division did not always print manuals that were unique to the individual models for the most part. The very early Model A and D "Kohler Power & Light Plant" models did have their own printed owner's manual that contained literally everything you needed to know, including parts data. Also understand that Kohler built the complete unit in these cases as well - engine and generator.

Beginning in the 1940s, possibly due to the war, Kohler began building generators in larger sizes. This precluded their ability to produce engines for the larger sets, as they had neither the engineering expertise nor the production facilities required to undertake such a project. As a result, they began to purchase their prime movers from a number of different companies, such as Waukesha and Continental, among others.

As the product line grew, so did the outside engine suppliers. However, as the engines changed, the generator and control portions of the units remained for the most part unaltered. A 10kW rotating armature generator was functionally the same as a 50kW generator.

With this in mind, Kohler began printing and providing individual manuals that covered the functional aspect of their units, that is, a manual that covered generator operation and troubleshooting, one for controller operation and troubleshooting, dry fuel systems, basic electrical troubleshooting, etc. These were bound into a booklet along with any engine parts manuals that were supplied by the engine manufacturer and a copy of the generator's wiring diagram/schematic.

When you post that you need a "manual" for your old Kohler whatever, you'll get nothing unless it's a later model. At this point in time, everything is out of print and Kohler is not keen about providing copies - even for a fee. They still have microfiche copies of everything, including the build ticket from the production line when your generator was manufactured - but these are not available to the general public any more.

So, if you need an engine manual, your best bet is to track down the engine manufacturer. If the engine is a Kohler, you can contact a Kohler engine distributor for more information. There will also be a separate nameplate for the engine with model spec and serial number of the engine. If it is a Kohler engine and it's water cooled, you have one of the L600 or L654 four cylinder engines - these were manufactured by the Engine Division, but sold directly to the Generator Division. As a result of this arrangement, you can only source parts for these engines from a Generator distributor using the generator model, spec and serial number. If you have questions or need to troubleshoot your controller or generator, you'll have to make due with the wiring diagram/schematic.

If you get a diagram for your generator, it will be laid out in the following fashion:

On the left side will be a "ladder" diagram, or schematic. This is used for troubleshooting and sequence of operation. At the top will be the battery and the generator. Below that will be the controller. B+ or positive is on the left, ground is on the right. You simply start at the upper left corner and trace the circuit down and to the right to see how the various parts operate.

On the right side is the wring diagram. This shows the physical location of the components in the generator and controls along with things like terminal numbers and wire colors. This is the side that you use to locate components in the controller or generator end.

To identify the proper wiring diagram, you MUST have the generator's "spec" or specification number. This, NOT the serial number, is what links the generator to a specific build ticket and design. With the spec number and a Kohler publication ES-913, "Specification to Wiring Diagram Cross Reference", you can find your wiring diagram.

Another way to identify the proper wiring diagram of the spec number can't be found is to locate the controller number. If you look closely on the outside of the generator controller, there may be a silver and black metal tag that says "Kohler Controller Number" which will have a number that begins with a letter that is followed by six digits, for example: "A-239467". The wiring diagram number for this controller will be one digit higher or lower.

Once you have this information, post on the Kohler Generator conference at the Stax and we'll be glad to help.



Once you have a wiring diagram number, you can call one of the legacy generator distributors (Kohler distributors who have been around many, many years) and get an electronic version of the drawing from them.

If you're polite and ask nicely, they won't typically charge for this.


Their Service Department is the one with the drawings, as they are a part of the master service catalog. The Parts Department either won't know how to help you or they'll get all confused and try to sell you a drawing or full set of manuals.

Two of the distributors I would recommend:

Buckeye Power Sales, Columbus, OH (and any of their branch operations, but Columbus is best as it's their HQ)

TAW Power Systems, Tampa (Riverview) FL

There are some others, too, such as Loftin Equipment in Phoenix and Bay City Electric in San Diego.

Be sure to have your drawing and spec number ready and just tell them you're a private individual who would like some information on your generator. They should only need the drawing number, but having a spec number handy will et them know you're prepared with the necessary information should they need it.


Baja Bob

what the heck does the symbol that looks like a square wave stand for? I have an excellent schematic,since it's a 3Kvs 115v system it's loads simpler than the one shown here, but I broke a circuit breaker and cannot find a replacement. It looks as if it was two thermal interrupters in one case. I'm hoping I can replace it with two separate breakers? I found another post of yours that explains the flow through a system that is brilliant but I was still unable to decipher that one component. Thanks so much for your help!

actually I've spent hours searching the www for a list that identifies these strange little markings. I took basic electronics in h.s. so I know a resistor from a capacitor but -unununun-this one mystifies me. and odd little triangles? I recall a little red book or something of that nature-it's been 50 years-Engineers Bible maybe? anyway it was full of useful info, conversion tables, map symbols and it seemed to me a table of electronic symbols including tubes-or "gate valves" as they were called. Guess it's time to head for Blacktail Books!



Just noticed your post - hopefully you're still checking in here....

The little square wave symbol on the older Kohler diagrams refers to the heater coil for the 1TS and 2TS thermal switches.

These are time delay circuit breakers in the case of the 1TS, and Klixon brand thermal protection devices for the higher current 2TS cranking circuits.

In the case of the 1TS, this typically had the coil running through the safety circuits such as low oil pressure, lack of output voltage and start disconnect. If one or more of these conditions existed, the circuit to the coil (square wave symbol) would be grounded, the coil would heat up, and a thermal element would open after a predetermined time to shut the unit down to prevent damage.

With the 2TS device, it would usually be in series with the exciter cranking circuit and would trip during excessive current draw or extended cranking to repent damage to the exciter windings.

Hope this clears up your understanding of the symbol. Do realize that Kohler sometimes too liberties with schematic symbols, so you may find others that don't exactly line up with what was typically used at the time the equipment was manufactured.



Hi Jim,
Thanks for this info - It probably will get me starting in figuring out the generator head and controller. I am wondering if these diagrams would suit my Kohler generator (Lister Petter diesel):
Kohler: 7.5RM081 - 63391A3.28
Lister Petter: 2410SR2 A23 (thus a 1973 engine and presumably a similar year generator?)
Thanks again!

dean l

just installed a brand new 20resc natural gas generator, will not start on thursday it was 20 degrees out, so installed a carb heater and regulator heater, have not done nothing with the parameters any ideas thanks

Art B

Hi everybody! I'm brand new on this forum. Kohler gen set is why I joined. Looking forward to interactions.

Here's the circumstance... regarding our 34' 1977 Tollycraft tri cabin pleasure boat’s - 7.5 kW, 4 cyl. gasoline engine Kohler generator – Plate Stamps: Model 7.5A23 / Spec 10606A / Ser No 472424

I have two very accomplished Kohler service shops trying to locate parts for our [what I believe is the original] 1977 Kohler Gen Set. Its serial number 472424 leads to RV system; not a marine system such as ours obviously is.

I also contacted Kohler HQ. They put me in touch with their primary parts distributor... boatswainlocker.com. One of their parts persons is trying to make heads or tails of this unusual/misleading serial number 472424 situation and if parts can be located to match our gen set.

Long and the short of what is happening and why I need to find answers this condition as well as maybe parts for repair:

So far no one can make heads or tails about the numbers on the plate on our Kohler gen set [read above and see photo]. One of the service shops could only locate that it may be an RV gen set. Boatswain Locker's person kind of agreed it had RV background from running numbers off the plate. The Boatswain Locker person is now searching all avenues at Kohler HQ in attempt to locate parts for this gen set.

To let you know why I seek parts: The gasoline motor of the gen set is in fine running condition. However - the electricity generating portion has a progressive, increasing problem - it continues to loose voltage production capability. In that... it now only turns out +/- 105 volts. Circumstance that occurred when the voltage got this low was the gen set could still run all electric appliances on our boat [fully electric boat] but the 105V output can no longer activate the house bank battery charger. The batt charger turns out 13.5 to 14.5 amps on shore power but only .5 to 1 amp on gen set power [while on gen set it used to do same as shore power]. I've checked this carefully by utilizing an exact same type of charger [I have a spare] and got same difference in amperage capability per shore power compared to gen set power.

One smart person mentioned that the reason the plate #'s lead toward RV gen set avenues is due to PO having replaced the electric generating portion with similar unit from an RV Kohler gen set??? Pretty good guess if you ask me! But, so far still unable to locate rebuild parts for the electric generating portion.

I’m also in action of checking the regulator on gen set to see if it is the culprit. Also going to run tests on Hz and running RPM of engine to see if per chance the motor’s accelerator/governor has become out of sync and maybe the problem is as simple as more RPM for more voltage???? That would be really nice!

Photos here are the gen set and its plate. If anyone has input regarding this dilemma of gen set reduced voltage problem as well as a way to locate parts availability off a statistic tag with numbers that make little sense regarding an obvious Kohler marine gen set... It Would be Much Appreciated!

Happy Gen Set Daze! - Thanks! – Art B




You posted in the wrong thread. Create a new post in the main forum as most people won't see this one.

Some observations:

1.) Serial number means nothing. It's the spec or specification number that's used to identify the parts and type of unit.

2.) Based on the model number, the rest of the nameplate data appear to be correct. A 7.5A model would never be in an RV, it's a marine unit, the "A" indicating automatic or demand starting.

3.) There is no regulator in this unit. I suspect you have a bad selenium rectifier, a common problem in older rotating armature units. If you look in the controller and see a big square set of metal fins, you've got a selenium rectifier. The replacement part is about $25.00 in the aftermarket, Kohler's "kit" is far more expensive if it's still available. DO NOT run the unit with a bad rectifier. If it fails it will damage other, far more expensive parts.

4.) I haven't seen one of those mufflers in years. At one time I believe there was a recall on them due to cracking.

5.) Call Bay City Electric in San Diego about this. They're a legacy Kohler distributor and will know exactly what it is and how to identify parts. If your service people are trying to work off the serial number, they don't know what they're doing. Serial numbers don't mean squat on a Kohler, they're basically for identifying a specific unit and mean nothing relative to parts or how it's built.

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Art B

Thanks LWB!

Since posting I've been in touch with really in-tuned old-boy Kohler mechanics in New England. I've five procedures that include , rebuilds, new parts and clean ups. I'll also record your suggestions. Plan to post results I get when completed. Will be in January at earliest.

Happy Kohler Gen Set Daze - Art ;)


I have a kohler generator 10cce serial # 485205.
Need help help on troubleshooting. It will crank up and run as long as I hold the starter button. Checking to see if anyone has a flow chart to help troubleshoot
Thanks Kenny


RR, You've posted in the wrong thread. Start a new thread with an appropriate title, so that it will be properly visible.