I'm no mechanic, need help...

[Bange]

Is the fuel new or old?

 

[ft_motors]

Background:
Cub Cadet Z42
Kohler 7000se.
Had issues with the carburetor last fall & stored over winter with the carb disassembled.
This week I replaced the carb, plugs, fuel pump oil & filter.
It fired right up and but smoked a lot initially, but subsided and won’t idle smoothly.

Suggestions?

Thanks

Your engine runs lean. Did you replace your carb with a genuine Kohler carb or knock off carb? The knock off carbs are manufactured poorly therefore the air/fuel ratio is incorrect.

 

[Jim363]

Background:
Cub Cadet Z42
Kohler 7000se.
Had issues with the carburetor last fall & stored over winter with the carb disassembled.
This week I replaced the carb, plugs, fuel pump oil & filter.
It fired right up and but smoked a lot initially, but subsided and won’t idle smoothly.

Suggestions?

Thanks

Possibility some of smoke and fuel line debris is blocking exhaust. Might check muffler and clean it out

 

[Johner]

Did not read all the responses, had a similar problem , Tiny O rings on the main jet could be the problem idling.

 

[Tiger Small Engine]

Did not read all the responses, had a similar problem , Tiny O rings on the main jet could be the problem idling.

Kawasaki engine you screw oil dipstick to left until it drops on threads then check. Briggs and a Kohler you screw in all the way. Honda take out dipstick and place it in without screwing it to read proper oil level.
Engine is not running rich, it is running lean and hunting and surging. Check “smart choke” if equipped as suggested first for proper function. Then check for air leaks in intake gaskets. Then start trying to adjust air/fuel mix on carburetor if equipped. Then you have to drill out jet as last resort. Aftermarket carburetors on Kohler engines specifically are hit and miss. Otherwise, this engine will never run right or make proper power. Or, get original carb working properly or bite the bullet and buy sniOEM carburetor.

 

[chuckpen]

I did not see a governer spring on the governer rod/shaft. Get one if missing and replace. There is some black tie wire or such, get that off. Choke is closed in video, as others have mentioned. The choke assembly is not assembled correctly. broken, and / or not properly connected to the carb, or, the choke mechanism on the other end is not installed correctly / hung up / broken. This link gives a lil overview of Kohler auto-choke on a mower but not specific to yours. This may help you understand how these chokes work.

 

[ILENGINE]

Kawasaki engine you screw oil dipstick to left until it drops on threads then check. Briggs and a Kohler you screw in all the way. Honda take out dipstick and place it in without screwing it to read proper oil level.
Engine is not running rich, it is running lean and hunting and surging. Check “smart choke” if equipped as suggested first for proper function. Then check for air leaks in intake gaskets. Then start trying to adjust air/fuel mix on carburetor if equipped. Then you have to drill out jet as last resort. Aftermarket carburetors on Kohler engines specifically are hit and miss. Otherwise, this engine will never run right or make proper power. Or, get original carb working properly or bite the bullet and buy sniOEM carburetor.

The only one on your list that screw the dipstick in is the Briggs. Kohler is set on top of the threads also. There was an issue with one engine that they said to screw the dipstick in but that changed after the dipstick replacement service bulletin That engine went from 64 oz to 56 oz oil capacity.

 

[TobyU]

Looks like you're choke is in the closed position and it's only being forced open because many of those are on a spring and they can work against the spring and yours is bouncing back and forth as the engine surges.
This could just be that the choke adjustment from the cable needs to be proper so the choke won't be forcibly closed all the time on its spring or you could still have a partial restriction in the carburetor and it may need some choke to continue to run because surging is the first sign of that but that's the main problem now.
You also need to check your oil and make sure it's not overfilled and not thinned out with gasoline because often a bad carburetor will allow fuel to migrate into the crankcase which is referred to as fuel migration or oil dilution.
If your oil is just oil and add a safe level like not over 3/16 of an inch above the full mark then it certainly not going to harm it to run smoking like that as it will probably clear up but you can see the black soot on the side of the frame back there from the choke being closed because it's running excessively rich and Rich equals black smoke too but over the course of last year and such you could have got some oil puddling in your muffler and that will take about 20 to 30 minutes to burn off.
Even if you have a blown head gasket the only thing it's going to hurt is it's going to carbon up your plug but I highly doubt you have a blown head gasket on a 7000 series Kohler.
You can see that butterfly in the throat of the carburetor and it should be only closed fully when the engine is turned off and you pull the choke lever or set your control to full choke.
As soon as you turn off the choke which should be after you start the mower or as soon as you put the throttle speed in the full running position if it's a combination choke throttle lever then that butterfly should be completely open which means horizontal in the throat so it does not block any air flow.
It's also very possible you have some linkage issues or it's installed incorrectly. I never recommend people take carburetors off their mower or actually take anything apart because it's just far too easy to mess them up..
Most every car clean out or repair can be done with the carburetor still on the machine so there's really no reason to remove the carburetor and it removes the potential for other problems non-related to the actual first problem.

 

[TobyU]

He probably took the carburetor off because everyone often seems to think it’s the carburetor. So the parts changing begins…

Yes, and most of this is because of the evil youtube!
I tell people all the time to stay away from that and away from that rabbit hole because most every video I see either does things the wrong way completely or at least they do things the hard way.
Most people do come up with the proper diagnosis but that's because we can come up with that right now. About 80% of all starting and running issues on lawn mowers especially push mowers are caused from lack of proper fuel delivery specifically lack of enough fuel which is almost always caused by the carburetor not doing what it should or being as clean as it needs to be.
So they've got the diagnosis right but it's their method of going about fixing it that is either flawed or just done the hard way.
Anyone who thinks they're competent enough to take off the carburetor and install a new one should be just as competent to fix the problem and leave the carburetor still on the machine.
I literally do hundreds of these in an eight-month cutting season and I don't remove 10% of them from the mowers.
The fastest is on the old school Briggs which I can do in 6 to 8 minutes but let's just say 8 minutes max.
The new briggs takes me 10 to 12 if I'm not in a hurry.
These people on YouTube take the carburetor off and lay it out on the table and everything like that and by the time they have it all back on the machine and running they spent between 30 if we're lucky to typically at least 45 minutes.
I don't really have time for that as I have 50 other mowers sitting there to fix but regardless it's just a waste of time.
That expression works smart or not harder it's not really what I'm saying I'm saying work smarter! Work smarter and work quicker. Sometimes it is a little harder but it gets the job done and it does it more quickly and it's actually less work it's just a little more tedious work in some situations.
But let's face it, anyone who is replacing a carburetor or working on these small engines who can't handle tedious work, probably should "step away from the toolbox".

 

[Tork Ranch]

Have a Kohler, it ran nice for 5 min. then started coughing surging and smoking. Took it to the small engine repair shop, they charged $160.oo said they did a carb job and changed the oil. I took it home , started it up 5 min later it was doing the same thing. I checked oil the next day, crank case was "full" (of oil/gas mixture). I changed the oil and fuel pump (pump had a hole in the diaphragm, and was pumping most of the gas into the crank case). It runs like a dream now. Good luck.