kohler command 25

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  #1  
Old 01-10-09, 07:21 AM
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Question kohler command 25

Hello, I have a Kohler command 25 on a vermeer cs252 stump grinder. The breather tube that comes up from top center of engine and connects to the carb is spitting fuel out back in to the carb. causing it flood and shut off smokking because of too much fuel. I would sure be greatfull for any advise
 
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Old 01-10-09, 08:52 AM
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Please post the model and spec. no.
 
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Old 01-12-09, 04:16 PM
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The model # ch25s
The spec # 68628
 
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Old 01-12-09, 04:34 PM
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If it's spitting fuel out of the oil breather hose, then you might want to check your crankcase and see if the oil is contaminated with gas. If the carburetor is flooding fuel and the crankcase is full of gas, then when the engine is started it will blow out the breather into the carburetor via the breather hose and choke down the engine.

If your crankcase has fuel in it, be sure to change the oil and filter after you repair the source of the contamination.
 
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Old 01-12-09, 05:02 PM
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yes there is fuel smell in the oil, but it dosent spit fuel right away I was just out there looking at it. I started the engine and it ran perfect for about 5 min. then it bogged down and smoked then smothed right out for a few min then repeated.

I was told it could be the acc pump so i tore the carb down cleaned it out, everything looked great.
 
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Old 01-12-09, 05:22 PM
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How is the oil level? It can take a few minutes of running before enough fuel/oil builds up in the breather and then starts pouring out the breather tube. If the oil level is very far above full, then this is most likely the problem. A leaking accelerator pump causes a constant "rich" condition, but rarely chokes the engine completely.
 
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Old 01-12-09, 07:18 PM
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I do not think breather tube is causing or flooding the carburetor. There is no fuel source to the breather tube.

The function of the breather tube that connects to the carburetor evacuates gases, not gasoline, from inside the engine's crankcase. This is an emission control function where the carburetor is sucking these gases into the combustion chamber to burn them.
electronic fuel injection

I suspect your problem will be carburetor related.

Find the parts breakdown for your engine and identify the part the fuel is coming from.

Parts lookup link:
http://www.milacalawn.com/parts.asp

Service manual link:
Service & Owners Manuals - Service & Support - Kohler Engines
 
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Old 01-12-09, 07:32 PM
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Airman,

I have run across numerous Kohler engines with carburetors that have leaked fuel into the crankcase and diluted the oil with gas. If the engine is run with a crankcase full of gas, the breather will fill with fuel/oil and then the overflow will blow out of the breather tube directly into the carburetor, and cause the engine to choke down and die. They also will usually smoke quite a bit as well.
 
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Old 01-12-09, 07:41 PM
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Originally Posted by 30yearTech View Post
Airman,

I have run across numerous Kohler engines with carburetors that have leaked fuel into the crankcase and diluted the oil with gas. If the engine is run with a crankcase full of gas, the breather will fill with fuel/oil and then the overflow will blow out of the breather tube directly into the carburetor, and cause the engine to choke down and die. They also will usually smoke quite a bit as well.
I have seen the same and you are perfectly right this could be the problem or at least the owner must verify this. I was not even thinking in that direction when I posted. Good catch.
 
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Old 01-13-09, 10:40 AM
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yes thats exactly what its doing if i pull the vent tube off it wont bog down it runs perfectly but still spits fuel out of breather tube. I just dont know how to fix the problem. or even where else to start.. Thank for help so far.
 
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Old 01-13-09, 12:06 PM
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Fuel getting into the crankcase is caused by carburetor float needle not seating allowing fuel to flow continually into the carburetor and it migrates into the crankcase. Could be trash under the needle or varnish build up in the needle cavity. Remove the float and needle. Using a Q-tip wet with metal polish, polish the needle cavity. This will remove any varnish that may cause needle drag. Fuel lines often deteriorate and the material can enter the carburetor causing the needle not to seat. Inspect fuel lines and replace if needed.
 
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Old 01-13-09, 01:50 PM
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I just checked and cleaned carb agin needle and seat good. someone told me to check the reed valve so thats what im going to do right now, hope for the best

by the way what should the compression be on that kohler I just checked it both cylinders are right at 150lbs turning it over for a few seconds?
 
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Old 01-13-09, 02:25 PM
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You may have the carburetor fixed, but you need to be sure to drain your crankcase and refill to proper level with fresh motor oil. Continuing to run engine with oil diluted with gas will cause major engine damage, and if the oil level is excessive you will still get oil and gas spitting out the breather tube.

You can get a service manual for your engine at the Kohler website. www.kohlerplus.com
 

Last edited by 30yearTech; 01-13-09 at 02:43 PM.
  #14  
Old 01-13-09, 04:10 PM
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ok I changed the oil and filter flushed it out put in new oil dead on the full mark ran perfect for 45 min. checked oil agin and good ways over full. So I pumping full into the crank case still. Is it possible to get in through the fuel pump that is ran off of the valvecover on this engine. Thanks agin for all the advice guys.. I just dont know where else the dang fuel is getting into the crankcase. time for a beer lol..
 
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Old 01-13-09, 04:53 PM
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Yes with certain types of fuel pumps, it's possible for fuel to enter the crankcase from the fuel pump if the pump diaphragm is ruptured.
 
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Old 01-13-09, 05:48 PM
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The parts list I looked at did not show the fuel pump for your engine. Is the fuel pump on your engine separate from the carburetor? Is the fuel pump connected to the carburetor with a fuel house? If this is the case, a ruptured pump diaphragm will not flood the carburetor.

Continuing to get fuel in the crankcase indicates the carburetor float needle is still not seating. Inspect seat area of the needle cavity for trash or a scratch on the seat. Have you found trash? If you did, you must eliminate the source.

Make a polishing tool by wrapping the end of a wooden meat skewer with cotton. Wrap just enough cotton to allow a tight fit in the needle cavity. Apply metal polish to the cotton and turn the skewer back and forth to polish the needle seat. After polishing, clean the area with solvent and install float and needle. Turn the upper carburetor upside down, so the float is placing pressure on the needle. Wet the needle with a few drops of solvent. Apply approximately 5-PSI air pressure to the fuel inlet fitting. If the needle holds pressure, it is seating correctly. If it will not hold pressure the problem is with the seat or the needle. The needle is included in the repair kit. If the seat is the cause of the leak you may be able to repair it and if not a new carburetor will be needed.

This pressure test is a common test for carburetor float needles. Oddly, it is not in the service manual for the CH25.
 

Last edited by Airman; 01-13-09 at 07:05 PM.
  #17  
Old 01-13-09, 07:26 PM
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Airman,
The parts list for his engine indicates a fuel pump mounted on the valve cover. Poster indicated this as well. He also indicated that the engine ran good for 45 minutes but the oil level increased with fuel contamination. If the carburetor was flooding to a point that excess collected in the crankcase while the engine was running, I don't think it could have been running very well.

I am not sure but I think this type of fuel pump is activated mechanically by a lever that is operated by the movement of one of the valves rocker arms, it's also possible that it could be operated by crankcase pulse. In either case, don't you think it's possible for fuel to enter into the crankcase via the fuel pump if the diaphragm has a leak?? That's my thinking, if the engine is running good, I can't think of another way for fuel to enter the crankcase while the engine is running.
 
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Old 01-13-09, 07:43 PM
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Originally Posted by 30yearTech View Post
Airman,
The parts list for his engine indicates a fuel pump mounted on the valve cover. Poster indicated this as well. He also indicated that the engine ran good for 45 minutes but the oil level increased with fuel contamination. If the carburetor was flooding to a point that excess collected in the crankcase while the engine was running, I don't think it could have been running very well.

I am not sure but I think this type of fuel pump is activated mechanically by a lever that is operated by the movement of one of the valves rocker arms, it's also possible that it could be operated by crankcase pulse. In either case, don't you think it's possible for fuel to enter into the crankcase via the fuel pump if the diaphragm has a leak?? That's my thinking, if the engine is running good, I can't think of another way for fuel to enter the crankcase while the engine is running.

I guess I really should not be sitting here MULTI-TASKING.....laptop and TV.

I will look at again in the morning.
 
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Old 01-14-09, 07:13 AM
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I really goofed this one. No more responding to posts while sitting in front of the TV. I missed the statement, “fuel pump that is ran off of the valvecover on this engine”. I guess it is plausible an internal failure of the fuel pump could result in fuel being drawn into the crankcase.

I finally found the fuel pump on the parts breakdown. It is in the Head/Valve/Breather section and not Fuel System as these normally are.

I guess the part that confused me was the first statement, “The breather tube that comes up from top center of engine and connects to the carb is spitting fuel out back in to the carb. causing it flood and shut off smokking because of too much fuel.”

This statement does not say, an oil fuel mix is coming out, it says fuel comes out. Then he said, “causing it flood and shut off smokking because of too much fuel”

I guess it is plausible an internal failure of the fuel pump could result in fuel being drawn into the crankcase.

Taswanger,
I suggest you speak with a Kohler representative. He may have knowledge of fuel pumps allowing fuel to enter crankcase. They may be interested in knowing your problem and who knows may authorize out of warranty repair. I looked for service bulletins and do not see any concerning this problem.

Kohler website:
The Power More Professionals Demand - Kohler Engines

Kohler 24 hour customer service. 800.544.2444
 
  #20  
Old 01-14-09, 10:19 AM
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ok first iwant to thank airman and 30 year teck for all your advice. I got it licked now there is only two places to get fuel in the engine period, the carb and that fuel pump on the valve cover. so I new it wasent the carb i tore it down three times. I just tore the fuel pump down and bingo the diaphram was ripped, pumping fuel right down the cylinder into the crankcase. So the fuel was thinning out the oil enough to blow back up the vent tube....SO THANKS AGIN AIRMEN AND 30 YEAR TECK FOR THE ADVICE. I think we all learned something this time.......
 
  #21  
Old 01-14-09, 06:37 PM
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Your welcome! Glad you got it all figured out. The inside of your engine should be pretty clean now, with all those oil changes....
 
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