Kohler engine wont start, was running fine

[ottsm 23]

A few weeks ago my Wheel Horse would start fine but would start losing power and then stop.   If I waited awhile it would start but then soon stop again.  If I left it sit overnight it would run fine for awhile but then would stop eventually and repeat the same symptoms.  I replaced the fuel filter thinking it might be plugged (later when the fuel all dried up I tried blowing through it and it appeared to be plugged).  With a new fuel filter I mowed last week and everything worked fine.  Today I went to start the tractor and it would not start, didn't even try to fire off.  I put the spark tester on and that tested okay (which ruled out the seat switch also).  I sprayed some starter fluid onto the air filter and no luck.  Removed the air filter to try and spray directly in but it appeared to be flooded with plenty of fuel and when the engine was cranking I noticed that it was puffing out the carburetor.  Believe this is a K321 (14HP) and was rebuilt several years back.  It's a cast iron block with an aluminum head.  Got to think it's a stuck valve?  Just kind of weird how it was fine last week, was doing nothing unusual while running and when shutdown didn't make any strange sounds or anything.  I had to mow grass so I used my other wheel horse tractor (twin engine) and by time I was done it was getting dark.  Tomorrow I'll be trying to find my old compression gauge, or I'll take the spark plug out and crank it and observe.  I'll try and look down the intake (take the carb off If I have too) and I'll remove the muffler and check and see If I can see the valves.  I think I should be able to see them if I remember correctly.  I guess I could remove the valve cover while at it.

Anyone have any thoughts? 

 

Edited September 14, 2023 by ottsm

[rmaynard 14,932]

First thing is to figure out if it's fuel or spark. What model are you working with? Is the vent in the gas cap plugged? Fuel pump going bad? Have you checked the points? Sparkplug? Condenser? Is the float valve stuck causing the carb to flood? Lots of areas to check.Start with the simple stuff first. A good running engine usually start running bad due to simple things. With all the gurus who hang out here, someone will come up with an answer.

[Achto 26,612]

8 hours ago, ottsm said:

I put the spark tester on and that tested okay (which ruled out the seat switch also).

 

A spark tester will only verify that spark is getting to the plug. First thing that I would do is check the spark plug to see if it has fouled out. 

[Pullstart 59,867]

 Maybe verify the points gap, and the points are clean.  I’ve had dirty points give intermittent spark and not enough juice to fire off.

[Ed Kennell 35,935]

9 hours ago, ottsm said:

  I sprayed some starter fluid onto the air filter and no luck.  Removed the air filter to try and spray directly in but it appeared to be flooded with plenty of fuel 

So, it has fuel .       Install a new plug.   Clean and set the points to 0.020".    

[Pullstart 59,867]

2 hours ago, Pullstart said:

Maybe verify the points gap, and the points are clean.

 

42 minutes ago, Ed Kennell said:

Clean and set the points to 0.020".    

 

This applies to your K series as well…

 

 

[953 nut 51,959]

As mentioned by Bob, Dan, Kevin and Ed an ignition tune-up should be done. Another thought that comes to mind is the fuel you are using. If you use gasoline with ethanol in it please STOP! Ethanol can cause fuel system problems and cost you time and money. You can find a station near you that sells real gas using this website, https://www.pure-gas.org/

[Sailman 1,134]

First thing I would do is replace the spark plug. That may not solve it but I can't count the number of times a simple plug replacement got my small engines going.

[Gasaholic 183]

3 hours ago, Sailman said:

First thing I would do is replace the spark plug. That may not solve it but I can't count the number of times a simple plug replacement got my small engines going.

And more than once, I have replaced a brand new out of the box champion plug with another new one to fix a no-start .. moral of the story: "New is not the same thing as Good" 

[Ed Kennell 35,935]

2 hours ago, Gasaholic said:

: "New is not the same thing as Good" 

That's why I like to swap questionable parts into a good running tractor for testing before buying new parts.

[ottsm 23]

Thanks for all the input.  I'll be working on it shortly now that I'm home from work.  What bothered me was the puffing out the intake, after I took the air filter off and cranked it, it was puffing the air/fuel mixture out the intake (misty looking). 

[ottsm 23]

Removed spark plug,  I cranked it a few revs and nothing is coming out the spark plug hole, just out the intake.  Not sure what the effect the ACR would have on this crude test but I have to think it would puff something out the spark plug hole.

 

[ottsm 23]

See attached

[ineedanother 1,366]

9 minutes ago, ottsm said:

See attached

IMG_0171.MOV

The spark plug hole needs to be covered to create vacuum to draw the fuel into the cylinder. Cover the hole with your thumb when you crank it to see if you draw fuel in... Either that or crank it with the plug in and then see if the plug gets wet.

 

More to consider, but this is one step.

[ottsm 23]

Covered hole with thumb, don't feel any suction.  mist still goes out intake.

 

Edited September 14, 2023 by ottsm

[ineedanother 1,366]

I'm afraid you're going to have to dig a little deeper. I would pull the head first to see what the valves are or are not doing. It sounds more and more like one of them has an issue.

[953 nut 51,959]

3 minutes ago, ineedanother said:

I would pull the head first to see what the valves are or are not doing.

If your intake valve is not closing the compression from your cylinder going backward through the venture of the carburetor will draw fuel up and blow it out the air intake. 

[ottsm 23]

Ok, already getting to dark out to work (days are getting shorter) so it will have to wait.  I found out where to order the parts, they seem to have everything for the Kohler engines.  Engine has 9 head bolts, engine decal is gone but I'm sure I was told it was a 14HP so it should be the K321.  I'll pull head tomorrow.

 

Edited September 15, 2023 by ottsm

[ineedanother 1,366]

2 hours ago, ottsm said:

I found out where to order the parts, they seem to have everything for the Kohler engines.  

Too soon to do that though. A good diagnosis of the problem is the first step. 

[953 nut 51,959]

12 hours ago, ottsm said:

Engine has 9 head bolts

K-241, K-301 and K-321 all have nine head bolts.

13 hours ago, ottsm said:

I cranked it a few revs and nothing is coming out the spark plug hole, just out the intake

Was anything coming out of the exhaust pipe? If not you could have a broken cam shaft.

[ottsm 23]

Stuck intake valve, engine look fairly clean except for the horn of the intake valve.  It has some black crust that easily broke off (guess that is what the manual refers as "coking").  I put some penetrating oil and tapped it with a mallet and it when back in, must have got a little of the carbon trapped in the valve guide.  Think I know what started this, I was burning some really old gas up and when I went back to the new guess it must have broken some of the buildup off, just a theory although the manual states that "coking" is normal.  

 

 

 

 

[953 nut 51,959]

13 hours ago, ottsm said:

Stuck intake valve