Simplicity Legacy w/25hp Kohler Command running really rich

[RandyT]

This is an Analog Spark Advance Module engine. So the issue could be with the one of the two ignition modules, or the ASAM itself. Either way I would do the 24 755 308-A ASAM to MDI conversion.

The other thing is the CH25 engines had issues with blown head gaskets. On the Command twins there is no decompression system but wouldn't be bad idea to pull the valve covers and make sure the push rods are in place and one valve isn't sitting higher than the other.

 

[MossRoad]

I have a Kohler command CH25. I had a similar experience. In my case (may not be yours), on the cylinder that's not firing, the nut that holds the rocker arm came loose, the rocker spun sideways on it's post, and that let the pushrod come out from under it. So the valves on that rocker would not function. I was lucky, in that all I had to do was put the pushrod back under the rocker arm, put the arm back in position, and re-torque the nut.

So it might be worthwhile to pull the valve cover on the side that's not working.

In my case, it was the side with the oil filler cap, so I looked in there and that's how I saw it.

Of course, one of the valve cover bolts snapped off when I was removing the cover, but that's another story.

Good luck in your troubleshooting.

 

[California]

mouse chewed wiring that went from the magneto to the coil packs. Just enough insulation chewed off to render the one cylinder inoperative with the air shield ... installed.

Reading that brought back a nightmare. 70's 400 ci Wagoneer. The vacuum advance caused the condenser wire to move, and ground against something to fire at the wrong time during starting and under hard acceleration. Easy fix ... ... ... after I found the problem.

The pro mechanic (well, gas station employee) I bought it from hadn't figured it out, so I bought it cheap. We both thought for a while that the car needed an exorcism.

 

[macindude]

Welp... This is the intake pushrod from the #1 cylinder:



Now, to figure out what caused that!

 

[tomplum]

Nobody stuck a Briggs and Stratton sticker on it, did they? You got this? At least you have a good side to compare things like guide positioning, how far the valves are protruding from the head which helps to determine seat and guide health, how free the valves cycle etc. How many hours and are you good about maintenance?

 

[MossRoad]

Welp... This is the intake pushrod from the #1 cylinder:

View attachment 823420

Now, to figure out what caused that!

As I mentioned before, is the nut loose on the rocker arm for that?
Mine actually pushed a hole through the composite valve cover.

 

[macindude]

Nobody stuck a Briggs and Stratton sticker on it, did they? You got this? At least you have a good side to compare things like guide positioning, how far the valves are protruding from the head which helps to determine seat and guide health, how free the valves cycle etc. How many hours and are you good about maintenance?

I'd have to look at the hours. It's well past 1000 hours.

As far as good at maintenance, I've been working on lawn tractors that belonged to my dad and then to me since I was little (49 now), and I took a 1-week course in small engine repair once upon a time. However, I'm clearly not doing it very much, because I still have all my 10mm sockets and wrenches.

As I mentioned before, is the nut loose on the rocker arm for that?
Mine actually pushed a hole through the composite valve cover.

They may have both been loose - As soon as I got the valve cover off, both pushrods and rocker arms were loose (rods fell right out of their spots in the arms).

Got a suggestion on Facebook that maybe a guide moved due to heat. I'm not sure how I'd be able to tell. I'm going to get the whole cylinder head kit for #1, and probably at least do a new head gasket on #2 and torque everything properly while I've got it apart.

 

[tomplum]

Comparing both heads is probably your best friend. Typically Kohler heads don't come loaded, so watch close that you get what you want.

 

[macindude]

Comparing both heads is probably your best friend. Typically Kohler heads don't come loaded, so watch close that you get what you want.

Loaded?

FWIW, I was planning to buy the full kit, P/N 24 818 01-S that includes the head, new valves/springs/rockers/rods, gaskets, hardware, etc:

 

[tomplum]

Ah. Maybe I should change that to any Kohler head that I'VE ever needed didn't come loaded. (Just the bare head)