Kohler 26 running rough

[r6wild]

I was getting ready to store for the winter decided to do some maintenance first. Changed fuel filter, oil, cleaned carb, new air filter and plugs. The motor sat for a week when I cranked it up I noticed,it sounds like its missing at half throtle or better but it idles fine. It also hesitates when I throtle it up and somtimes with a slight backfire. Both plugs are gapped at .030 and firing. Any ideas would be appreciated.

[lawnmaniac883]

Plugs are both sufficiently torqued down? Did you remove/dissassemble the carb? If so, I hope you blew out all passages after spraying with carb cleaner? Not sure if the mixture settings can be adjusted but if so, sounds like it is running a little rich.

[Restrorob]

A hesitation and backfire is a possible sign of a lean condition on the high speed circuit in the carb. To check apply a little choke and try throttling up, If it runs up Ok then the carb. needs to be taken apart and cleaned. If you did in fact do this already it needs to be done again and concentrate on the main jet and high speed circuit.

[Jman]

A 26 horse is fuel injected, what is the model and spec number of this engine?

[Restrorob]

A 26 horse is fuel injected, what is the model and spec number of this engine?

Boy do I feel like a idiot, Didn't catch the 26 up top ;)
Wonder how the carb. was cleaned if there isn't one :confused:
Your right It's always nice to have numbers.

[r6wild]

The carb was not taken off when I cleaned it. I just sprayed cleaner into the carb while it was running. Both plugs are as tight as a Texas hat band and it is a Kohler CV26S-69526. I tried to pull the choke out at many different settings.If it was out one quarter it would accelerate ok but once the RPMs leveled out it would start to load up and throw alot of black smoke. So pulling the choke out didn't solve the problem. Also the carbs mixture is non adjustable.

[r6wild]

Sorry for not mentioning the engine is not fuel injected. It must have been one of the early model 26hp before the EFIs. Its about 5 or 6 years old with 490 hrs.

[Jman]

The 69526 spec was built for Sears. Sears used to use a different horsepower rating than the ASE standard that was used at the time. With their rating standard it was 26 horsepower, by Kohler's standards used it was 25. THat's why I hate horsepower ratings, not as good as torque. Anyway. Take the carb off and have it overhauled, or cleaned out with a new kit installed in it.

[r6wild]

Update, rebuilt carb still ran rough. Took it to a kohler service center, mech. said it looks like its running rich he took the carb off and inspected and cleaned it. Still ran rough at half to full throtle. He suggested a new carb being the mixture is non adjustable so I broke down and spent the $200 on a new carb and as you would guess still has the same problem. Personally listening to it it sounds like an electrical miss could it be the timing or something any help would be greatly appreciated.

[Redneckn]

Air leak would be my guess after everything you've had done. Could possibly even be a head gasket blown. (internally)

I can guess on the internet all day. Being there is different. But I still think that some form of an air leak is to blame. And from my dealings with the Sears/Kohlers I would think a head gasket is quite possible.

[flman]

Hope this can help. Since you stated that you tried everything as far as carburetion goes here is a few things to check out on that stubborn miss.Not in any certain order.
1. Check for leaking intake manifold gaskets,you can see them pushed out visually.
2.Have a tech put a test on the SAM(SPARK ADVANCE MODULE)this will cause ignition problems which will make the engine act as if a coil is bad.
3.Take your plug gap to .025
4.Pop the valve covers just to make sure all is well

Hope this helps!

[r6wild]

Figured out the engine is running on one cylinder. Can anyone help me figure out if it could be the Rectifier-Regulator, Module ignition or the Module Speed Advance. Any help would be appreciated.

[r6wild]

Let me also say that when I pull the plug from the cylinder thats acting up it runs smooth but it is running on one cylinder. When I put the plug wire back on the plug it starts to run bad and back fire.

[Redneckn]

Figured out the engine is running on one cylinder. Can anyone help me figure out if it could be the Rectifier-Regulator, Module ignition or the Module Speed Advance. Any help would be appreciated.


I can say that it will not be the reg/rect as that is part of the charging system and has nothing whatsoever to do with the "firing". It could be the module or the SAM. I would have the SAM tested.

To test the Module: Point 1 is the little spade tab, point 2 is the larger spade tab, point 3 is the plug wire (inside the boot), point 4 is at the holes for the mounting bolts.

From point 1 to point 4 with your multi-meter set to read Ohms, you should have 945-1175Ohms.
From Point 2 to 4, should have 149-166 Ohms.
From point 3 to 4, should have 3750-7000 Ohms.

If yours tests within those specs, the module should be fine.
Double check your spark plug. May even swap the plugs to see if the "bad" side starts to run normal. If you are certain about the plug, nothing changes with plugs reversed, and the Module checks within the specs I gave. The SAM would be the issue. The red wire going to the same. When the key is in the "on" position, make sure that red wire has at least 8vdc on it. Really, it needs to have whatever your battery voltage is. If it does not, that would be the issue. But I dont think the voltage to the SAM is the problem because it will start and run. I dont know a way to test that think with a SAM tester.

Good luck.

[lawnmaniac883]

Is it possible he sheared the flywheel key?

[John Gamba]

Is it possible he sheared the flywheel key?


Or i could be almost sheared off????

[Redneckn]

Is it possible he sheared the flywheel key?

That is something to check but I would doubt that to be the issue. The flywheel key on a Kohler isnt like a Briggs. It's a beast of a key to start with. Plus, you generally will run into the situation where if the key is sheared (even partially) that it wont run at all.

But again, it is something to think about and to check as well as everything else. Mainly because on small engines, you can get so involved in the big complicated things that can go wrong, it's easy to overlook the the little simple things... *like being out of gas*:eek:

[r6wild]

Thanks for the help I will test the module tomorrow and post the verdict.

[JHugh]

I would remove the valve covers and check the rocker arms. I have seen a few 25 Kohlers with the same mentioned problems have the rocker arm stud retaining bolts back out of the head. The valves are working but not opening up all the way.

[r6wild]

Problem solved, a wire coming from the smart box to the coil had a loose connection, at the coil. Thanks for all the help. Wish I would have checked that before I bought the new carb.

[Redneckn]

Problem solved, a wire coming from the smart box to the coil had a loose connection, at the coil. Thanks for all the help. Wish I would have checked that before I bought the new carb.


Don't ya just love that kind of thing?
I blew $1600 for intake and heads on my Cougar not realizing that reason all this happened was because the radiator cap was faulty. The really fun part was it happened the day I bought the car. I got stuck out in the middle of BFE and had to wait almost 5 hours before I was able to get a hold of my tow truck driver and get him there and get the car back to my farm...