Go to the Kohler engine website. Plug in the numbers for a free service manual download for your engine.
Look in Sections 2 and 3.
Section 2 describes a cylinder leakage test kit. You can improvise if you are "handy". You don't really need the "percent of leakage gauge" for determining if the head gasket is blown.
Section 3 explains how to perform the cylinder leakage test.
In lieu of a "bona fide" leakage test you can remove the valve cover and peer into the push rod gallery while shining a good light in there with the engine running.
If the head gasket is leaking there, you will see the puffs of smoke/gases on each compression/power stroke.

+ to the big lug
- to the block ground
Touch the small and large terminals together to crank. Really, I've found just pull the head on a Kohler. You want to check reed valves too which are behind the head. Kohler has free svc manuals for your perusing pleasure. Enter as guest.

Here is a link that might be useful: Kohler manual

wabbout a plain old compression test?

A "plain old compression test" may not even accurately reflect the true compression on engines that feature a compression release.
A cylinder leakage test will reveal if indeed there is a loss of cylinder integrity................and can pin point the culprit component.

The "Cylinder Leakage Tester" costs $162.00. You say "if I am handy" I could improvise. I can certainly make something with tubing or 1/8" pipe, a gauge, and small valves to inject some air into the cylinder. What can I use for spark plug threads on my homemade device?

Here's an excerpt from Kohler's book.

Air escaping from crankcase breather ......................................................Rings or cylinder worn.
Air escaping from exhaust system ............................................................Defective exhaust valve/improper seating.
Air escaping from carburetor .....................................................................Defective intake valve/improper seating.
Gauge reading in âÂÂlowâ (green) zone ........................................................Piston rings and cylinder in good condition.
Gauge reading in âÂÂmoderateâ (yellow) zone ............................................Engine is still usable, but there is some
wear present. Customer should start
planning for overhaul or replacement.
Gauge reading in âÂÂhighâ (red) zone ..........................................................Rings and/or cylinder have considerable
wear. Engine should be reconditioned or
replaced.

If you notice, none of Kohler's "tips" indicate a blown head gasket. Would a bad head gasket be included under "improper seating"? What will I see/hear and, where will the air be escaping to if it is a typical blown head gasket?

While I'm having the engine held with the piston at TDC, do I pressure-up the cylinder and then close-off the source of air? Or, do I maintain a small continuous flow of air going to the cylinder and determine where the leak is coming from and how bad it is, by looking/listening?

I don't see any reference to the breather reeds. Will this air test reveal a problem if it is a reed issue?

"What can I use for spark plug threads on my homemade device?"

A hollowed out spark plug.

Walt Conner

While Kohler seems to have missed the mark a bit by not including a blown head gasket in their "rings or worn cylinder" remarks..................a blown out head gasket on an AIR COOLED engine will present itself as a leak into the crankcase if it blows at the pushrod gallery point, or if it blows into an oil return drain hole point.
If it blows elsewhere on the gasket perimeter it will present itself as a leak to atmosphere.

Spark plug hole adapters can be obtained at many auto parts centers. You may find them as "compression tester adapters".
As Walt suggests, an old plug with the center knocked out of it makes a usable fitting to build on.
I have made adapters in the past by using what was called "anti-oil fouling adapters". These things might not even be on the market any longer. They were essentially a threaded "cup" about the size of a sewing thimble (I hope thimble does not need explaining.......does anybody sew anymore?).
The plug was threaded into the cup and then the plug with cup threaded into the cylinder head. The cup recessed the plug away from the combustion chamber enough to minimize oil fouling on oil burning, worn out engines.

To determine which gasket is blown will still require looking into the pushrod gallery with the valve cover off, but it will be a clean inspection compared to running the engine to do the same inspection.

You may see what you're looking for with pressure is the cylinder or not. I haven't tried doing so on this engine as it has an ACR. Let us know what you find. If there are no external causes like fuel in the oil, overfilled, dipstick seals etc- it will likely need to be apart anyways. One cylinder fowling is a telltale sign.

I have many options now. Thanks everyone for your contributions. You can bet that I will return with the results or, with more questions.

Mownie, I do remember thimbles. I think I can vaguely remember needles made of whale bone! LOL

***"needles made of whale bone"***
You must be as old as me. :^)

Mownie: What about the sneaky little green words that are appearing in some of the questions sent in by us folks? Are they the work of the web-site, or are they the work of some folks who can't afford to pay for real advertising? RJ

rustyj, those sneaky little green words you see (along with a bunch of other ads) are something I never see anymore.
I can imagine they are the "cue word" advertisements put there by Garden Web to serve their paying advertisers.
This type of suggestive advertising identifies a select number of words in a text message and makes those words a "click enabled link".
If you click on those you get either a pop-up ad window or you will be redirected to a different web site.
Ever since I got Ad Block Plus software added to my Firefox browser those things and a bunch of annoying ads went bye-bye.