View Full Version : Kohler 23 Command Bogs Under Load

05-19-2009, 05:48 PM
Did a very extensive search while trying to diagnose the problem so if anyone knows a thread this was already discussed in, please feel free to post it here.

Engine is a CV23S-75590 that is brand new which served as a replacement for a 25hp Kohler that was on a Great Dane Chariot w/61 inch deck. It seems to run fine unless the blades are engaged then bogs down and blows a bit of black smoke out the muffler and blows a bit of gas out the carb when the pto is engaged. I checked the governor and carb to make sure they were properly adjusted and took the belt off the clutch, but the engine ran normally. Checked the plugs and they were really sooty.

Whenever the control levers are firmly applied or when the mower is going uphill, I can feel the wheel motors/pumps squealing as if the engine doesn't have power. It didn't do this when I had the 25hp kohler but it did bog down at the end of its service life of 2660hrs which is why I had to replace it. I expected to get very similar power out of the 23 but this is not the case. These Chariots came with the 23 or 25hp option so I'm thinking either something is improperly adjusted or simply not working. Thanks in advance.

carl b
05-19-2009, 09:33 PM
I have the same motor with mine the accelerator pump in the carb. was bad than i replaced it . it went bad 150 hours later . new carb. about 800 hours ago its been fine

05-19-2009, 10:15 PM
What is the wide open throttle no load RPM set at ?

05-19-2009, 10:38 PM
I have no idea since I don't have a tach- these engines only have the idle adjustment screws which are both set to the factory specs.

05-19-2009, 11:30 PM
LOL, I know all about these engines.....

If you don't have a tach you should purchase one Tiny Tach (http://www.tinytach.com/tinytach/gasoline.php) or take the unit by a shop and have them check the high speed RPM and adjust if needed.

If the RPM's are set too low that could cause your lugging problem, Dixie Chopper sets all Kohlers at 3750 no load just to give you a figure.

05-20-2009, 05:02 AM
non contact infared tacho
Uses a light beam onto reflective tape [works on diesel or any part that rotates ]
30--50 $$

The govenor has to be set up >>>>>as per factory instructions >>>>>

The governor spring cannot be changed . KOHLER springs are colour coded
SPRING must be installed in the correct holes on the linkage PERIOD


05-20-2009, 08:49 AM
I could adjust the screw that's on the throttle linkage which works with the throttle stop to increase rpms, but isn't there another way to increase high speed rpm? Manual doesn't say anything about it. Would that cause gasoline to blow (mist) out the carb and traces of black smoke coming out the muffler? Thanks again.

05-20-2009, 01:27 PM
Engine is under warranty so I took it in to have it looked it. Will update once I find out from them what the problem is.

05-21-2009, 09:24 AM
Just got an email from the shop that's doing the warranty work and they said the muffler is bad. I can understand a bad muffler causing power loss to an engine but what about the slight flooding when the blades are engages? Could a muffler really do that? When he was listening to the mower yesterday he said it sounded quiet and thought the muffler was restricting the engine but the guy I took it to before him that knows mowers told me it didn't sound good at all and that it wasn't the muffler...

05-21-2009, 12:23 PM
Could a muffler really do that?

Sure could, If the cylinder can't exhaust there's less room for fuel intake which can cause more spit-back out of the carb.

05-22-2009, 12:38 AM
And it could be the muffler I guess, but in 8 years I have had them leak, break, crack, rust,
and do all sorts of things, except I have never had that choke any of my engines.

So I would first check all of the spindles and pulleys and make sure they are all
turning freely and that none of the bearings are worn.
All along the belt path, get up in there and manually and visually make sure that thing turns like it should.
Also look for any debris, heavy grass or dirt build up, sticks, pine cones, anything...
Clear and clean it all up, if there's anything there.

It almost sounds like either a nasty bit of dirt build-up or a stick or something,
and if that's not it then there's a bearing someplace going, last but not least
make sure no pieces of frame or steel have broken as well, just in case, things
like an out-of-place steel belt guide could be rubbing...

A serious grass build-up underneath the deck perhaps?
Not sure, but might be worth getting underneath and cleaning that out as well.

Any of that will hold the belt back, causing drag on the engine.
Oh, one more thing, make sure the belt is following the correct path.

So, then...

Once all that is gtg, why then if it still doesn't run...
How's the air filter?
What about the spark plugs?

05-22-2009, 07:51 AM
Thanks again for all the posts. Always great to hear from everybody especially restrorob and topsites. It turned out to be a bad muffler so I found one off a parts scag and took it to the shop. It was an all day affair and I had a hard time sleeping cuz I had mowers in my head but the thing runs great and cuts great now. I only had to make two passes to cut like 1ft grass and it looks super clean. Stripes look fantastic as well.

When I was at the shop yesterday morning, they showed me how the muffler was restricting the engine flow by blowing compressed air through the exhaust ports. You could tell there was not enough air flow going through the baffles and there was a ton of blow back coming through one port while air was blown through the other. You could hear the loose baffle while shaking the muffler, something I should have done while putting on the new engine. Don't know why I did but at least I learned something new and that the mower is working.

Thanks again everybody and once again, it was nice to hear from you guys.