# Kohler twin engine fuel problem



## walker1 (Apr 27, 2009)

Hi, I have a Craftsman garden tractor with a Kohler twin cyl. engine- # CV20S, 20 H.P.

I had some gas that had trash in it and now the engine won't idle well. However, when mowing the lawn under full throttle it runs fine. I blew out the fuel filter, but no constant idle. 

I'm thinking of a carb kit from Sears, but is there a way to clear up this problem without taking the carb off? I'm not sure what else to check.

All feedback is appreciated.


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## 30yearTech (Sep 14, 2006)

What is the spec number off your engine??

It probably does not need a kit, but may have some debris in the low speed circuit of the carburetor, or a plugged pilot jet (depending on which carburetor your engine has).


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## walker1 (Apr 27, 2009)

30yearTech said:


> What is the spec number off your engine??
> 
> It probably does not need a kit, but may have some debris in the low speed circuit of the carburetor, or a plugged pilot jet (depending on which carburetor your engine has).


I have Kohler-#1205001, mod.- #CV20S, & Type- #65561.


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## walker1 (Apr 27, 2009)

walker1 said:


> I have Kohler-#1205001, mod.- #CV20S, & Type- #65561.


The carb is Nikki- #2485325S. 
Type/Spec- 65561

Is this all you needed?


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## 30yearTech (Sep 14, 2006)

You may want to drop the float bowl and have a look to see if there is any debris collected in there. If there is, then a good cleaning may be in order. You can likely clean out the carburetor without using any parts. You should be able to drop the float bowl with the carburetor mounted, but you will have to remove the air filter assembly.


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## walker1 (Apr 27, 2009)

30yearTech said:


> You may want to drop the float bowl and have a look to see if there is any debris collected in there. If there is, then a good cleaning may be in order. You can likely clean out the carburetor without using any parts. You should be able to drop the float bowl with the carburetor mounted, but you will have to remove the air filter assembly.


I d-loaded the Kohler service manual and am reading the schematics and tech stuff tonight. Correct me if I'm wrong, but doesn't cleaning the inside of a carb require taking the top section off 1st? I'm going by my Holly carb. days @ the race track. 

Unlike my chain saw this twin Kohler is a bulldozer. The only thing that ever slowed down the engine was deep puddles of water in the swale while mowing the grass. This is a primo engine!


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## 30yearTech (Sep 14, 2006)

The top part of this carburetor is the body. There is a plate on the very top, but I rarely ever remove those. The fuel flows into the float bowl first and is picked up by the main jet. This feeds the idle circuit, so if anything got in the carburetor from your fuel, it came from the float bowl area. This is also the easiest part to remove without taking the entire carburetor off, which is a little tricky.


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## walker1 (Apr 27, 2009)

30yearTech said:


> The top part of this carburetor is the body. There is a plate on the very top, but I rarely ever remove those. The fuel flows into the float bowl first and is picked up by the main jet. This feeds the idle circuit, so if anything got in the carburetor from your fuel, it came from the float bowl area. This is also the easiest part to remove without taking the entire carburetor off, which is a little tricky.


Hello, I worked on the tractor today. This carb has a solenoid attached to another part of the carb which goes into the bottom of the fuel bowl. I took those parts off and removed the bowl. There wasn't much inside the fuel bowl, but I cleaned all areas including the main jet with carburetor cleaner.

I did remove the top piece and noticed there was a small jet in there so I proceeded to spray the jet and the area. I then put everything back together and the engine cranked, but would not start. The battery started going down so I attached a battery charger to it. It finally started but stalled a couple of times. When I could keep it running I adjusted the low idle speed and the air mixture screw and the engine was smooth.

All seemed good so I drove around the yard with the cutting deck on. A few seconds later it stalled and would not start. I got it back in the garage and jump started the engine again. The tractor has an electric PTO and it did this to me a few months ago. It turned out the battery was no good.

I got the tractor running again and drove towards the shed. It died before I got there. I pushed it into the shed and hooked up the battery tender. The light was bright red which is bad, so tomorrow I'm bringing the battery to Pep Boys to have it checked. This happened exactly like this back in May and at that time the tractor needed a new battery.

The good news is after cleaning the carb and making adjustments it idled fine. I'll let you know how I make out with the battery tomorrow. I can't think of any other reason why the tractor would die like that. Like I said, it did this to me once before. I'll get back to you. Thanks for your help.:thumbsup:


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## 30yearTech (Sep 14, 2006)

You may need to check the alternator output. The alternator should provide enough power to keep the engine running. It could also be a bad connection at the fuel solenoid or the ground wire to the carburetor. Did you make sure and reattach the ground wire, it should be attached to one of the screws on the top plate of the carburetor.


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## walker1 (Apr 27, 2009)

30yearTech said:


> You may need to check the alternator output. The alternator should provide enough power to keep the engine running. It could also be a bad connection at the fuel solenoid or the ground wire to the carburetor. Did you make sure and reattach the ground wire, it should be attached to one of the screws on the top plate of the carburetor.


To begin with I got a new battery yesterday and installed it. The engine started and ran until I attempted to adjust the idle mixture screw. Then it died. I was not able to start the tractor immediately. This morning it started and idled for about 10 minutes. I drove it out of the shed and it started surging badly after I put it in gear. I was able to drive it into the shed, but the engine died before I could attempt to readjust the idle mixture. What is even stranger is the engine does not start after it surges and stalls. The manual says to turn that screw clockwise until it seats slightly and then back off 2 1/4 turns to start the adjustment process.

I don't know how to check the alternator or where it is. The fuel solenoid has a wire coming out of it and it plugs into another end securely. The ground wire is attached fine and tight.

The original problem of not idling is gone. Perhaps I should have left the idle mixture screw alone as now driveability is gone. At this point in time I'm not sure what to do. I was thinking of taking the idle mixture screw out and looking to see if there's any debris in there. I ordered a gasket kit, but it does not have any screws or other parts.

At this point I look to you to possibly help me figure this out as it appears the idle mixture screw is causing the engine to surge and stall out. Prior to me touching it there was no driveability problem. The Kohler service manual states that screws should be replaced if there's a problem. Before this incident the idle mixture screw was never touched since the tractor was new 8 years ago and it always ran great.

Let me know your thoughts. Thanks, Walker


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## 30yearTech (Sep 14, 2006)

The problem could be fuel delivery to the carburetor. Can you tell if the fuel is flowing through the fuel filter alright?


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## walker1 (Apr 27, 2009)

30yearTech said:


> The problem could be fuel delivery to the carburetor. Can you tell if the fuel is flowing through the fuel filter alright?


I blew through the filter and didn't feel any obstructions in it. What else can cause an engine to surge? Solenoid? mixture screw? What else is there?


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## 30yearTech (Sep 14, 2006)

Have you checked the fuel pump delivery? It may have not be pumping fuel to the carburetor consistently.


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## walker1 (Apr 27, 2009)

30yearTech said:


> Have you checked the fuel pump delivery? It may have not be pumping fuel to the carburetor consistently.


I got a new fuel filter @ Sears & installed it along with new plugs. I cranked the eng. & noticed the new filter- (See through) wasn't filling with gas so I shut it down and sucked on the tank hose. That filled the filter and fuel line to the fuel pump. 

I then took out the idle/mix. screw and cleaned it off with a clean soft rag. There appeared to be a minimal amt. of blk. ring around where the screw had been seated since new and I wiped it clean. Turned screw in all the way, backed off 2 1/4 turns and the eng. started with no problem.

I let the eng. run for about 10 mins. @ about 1200 RPMs and turned the idle/mix. screw a little @ a time in both directions until I got the eng. pretty smooth. Unlike yesterday- the eng. didn't sputter & die when I turned the screw. 

It was raining so I engaged the PTO in the shed @ full throttle. It seemed smooth. Tomorrow I will try it in gear and see if the eng. surges in gear with blades off. That's when it died yesterday outside. 

Question: Should the fuel pump have sucked gas from the tank & filled the new fuel filter? I did it and it kept running. I thought the pump would pull the gas from the tank w/out my help.

What do you think now?


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## justin3 (Apr 10, 2007)

Sounds like your fuel pump isn't working properly, it should have pulled gas into the filter.


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## 30yearTech (Sep 14, 2006)

Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.


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## walker1 (Apr 27, 2009)

30yearTech said:


> Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.


Tomorrow I'll get the tractor out if it doesn't rain again. I have the hood off as it was hard to get to the carb. If it runs fine in gear @ high throttle I think the problem will be resolved. In the shed it runs fine @ full throttle with the blades engaged.


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## walker1 (Apr 27, 2009)

justin3 said:


> Sounds like your fuel pump isn't working properly, it should have pulled gas into the filter.


I agree with you. Tomorrow I'll road test the unit weather permitting.


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## walker1 (Apr 27, 2009)

30yearTech said:


> Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.


OK, I started the eng., no problem. Backed it out of the shed for 5' - it started sputtering/surging & I got it back in the shed just in time.

Took off the fuel line to carb- NO gas. Took off line from tank- NO gas. I sucked back & forth into the pump and heard/felt a diaphram moving. You say there are check valves in the pump? 

I don't think my tractor has venting from the tank. I took off the gas cap and no change. I guess it has to be the fuel pump. 

Do you both agree?


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## walker1 (Apr 27, 2009)

30yearTech said:


> Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.


Where to start. Took gas tank off and air blew it out. Had fuel pump & solenoid checked and they are OK. There was debris in the tank that caused partial fuel blockage causing surge/stalling under heavy load.

I thought I had it fixed yesterday. Tractor ran fine for 2 hrs. mowing the lawn. Great.

Today I started tractor, backed it out & 10' later it surged & stalled out. Gas IS getting to carb, so Monday I'm bringing carb to local Kohler repair shop. He blew out the tank and says the debris is somewhere in the carb. He will take it apart & dump it in chemicals to clean whole carb. It will cost $35 or so. 

At least nothing expensive broke. Price for solenoid is a whopping $88.00. Fuel pump is $32.00.

I guess by Tuesday all will be back to normal. Thanks for your input. :thumbsup:


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## 30yearTech (Sep 14, 2006)

Sorry walker, I have been busy and neglected to check back and answer your posts. Generally the fuel filters will keep the majority of crud from making it to the carburetor, but it does sound like there is something in yours. Best of luck and let us know how you make out.


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## walker1 (Apr 27, 2009)

30yearTech said:


> Sorry walker, I have been busy and neglected to check back and answer your posts. Generally the fuel filters will keep the majority of crud from making it to the carburetor, but it does sound like there is something in yours. Best of luck and let us know how you make out.


No problem. My situation has changed completely since I last posted to you. I have brought both the gas tank and the carburetor to a local Kohler repair shop and the mechanic thoroughly cleaned both units without finding anything. I put the machine back together and it started, but once again as soon as I drove the tractor with a load it surged and stalled out.

I called the mechanic and he said he would need the whole tractor to troubleshoot the problem. He's thinking possibly an electrical problem as it appears to be an intermittent problem. The entire fuel system has been cleaned and thoroughly checked without finding anything.

My dilemma is I have no way to get the tractor to anyone as I do not have a vehicle or trailer. I called Sears and they want $100 just to have a mechanic show up and diagnose the problem. They do not apply the hundred dollars towards the repair job which stinks.

It will cost me about $65 to rent a U-Haul to get the tractor to a shop. The local Kohler repair shop charges $45 to diagnose. Either way it's about the same money. However, Sears tends to be very expensive on both parts and labor. The shop I went to charges $65 an hour and the lady on the phone for Sears could not quote me any labor figure. I was informed that the mechanic diagnosing the tractor would tell me how much the job would cost after I pay him $100 to show up.

I am uneasy whenever somebody won't tell me what they charge by the hour or half-hour and I know Sears charges the most for any parts. I could use some advice on what your thoughts are on calling Sears versus a repair shop. Because this is an intermittent problem it could get expensive and sticky. I mean the problem might go away and then returned in a couple of weeks which might cost me a lot more money.

Please let me know your thoughts on this as I have to make a decision in the next few days. Fortunately, I mowed the lawn last week and we haven't had rain. I have not any problems with the Kohler/tractor since it was new eight and half years ago. As always thanks for your input.:thumbsup:


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## 30yearTech (Sep 14, 2006)

Have you tried running it with the fuel cap loose?? It could just be that the fuel tank is not venting good. Does your unit use a fuel pump??


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## walker1 (Apr 27, 2009)

30yearTech said:


> Have you tried running it with the fuel cap loose?? It could just be that the fuel tank is not venting good. Does your unit use a fuel pump??


Yes, I put the original cap back on and it vents excellent. I blew through the cap pushing gas to the carb through the fuel pump. Yes it has a fuel pump and it was already checked @ the Kohler shop.

What do you think about an electrical/wire problem vs. a fuel problem now?


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## 30yearTech (Sep 14, 2006)

It's certainly possible, although it would have to be an issue with the fuel solenoid. If it were an ignition problem, there likely would be no surging and maybe some after fire booms from the muffler. 

You could remove the plunger from the fuel solenoid and try running the engine this way. If it runs alright without the plunger then you can safely assume that there is an issue with either the after fire solenoid or the power supply to the solenoid.


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## walker1 (Apr 27, 2009)

30yearTech said:


> It's certainly possible, although it would have to be an issue with the fuel solenoid. If it were an ignition problem, there likely would be no surging and maybe some after fire booms from the muffler.
> 
> You could remove the plunger from the fuel solenoid and try running the engine this way. If it runs alright without the plunger then you can safely assume that there is an issue with either the after fire solenoid or the power supply to the solenoid.


I called Sears back today. It seems that they do apply the $100 trip/diagnostic charge to the job. I was misinformed by the last rep. What bothers me is the solenoid is so expensive. The tech is coming next Wed. 

I've spent too much time on this problem with no results and I have other duties that I've been putting off. Strange though- I see I'm not the only person with the same problem on this forum. Does that seem odd to you?


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## 30yearTech (Sep 14, 2006)

walker1 said:


> Strange though- I see I'm not the only person with the same problem on this forum. Does that seem odd to you?


I just worked on a John Deere with a Kohler twin (nikki carb.) today that was having a similar issue, but it was a gummed up carburetor that caused it. Cleaned it up and no more problems.

May be a similar issue but not necessarily the same problem causing it. If the others would post back with additional information then maybe we could see if anyone has figured anything out.


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## walker1 (Apr 27, 2009)

30yearTech said:


> I just worked on a John Deere with a Kohler twin (nikki carb.) today that was having a similar issue, but it was a gummed up carburetor that caused it. Cleaned it up and no more problems.
> 
> May be a similar issue but not necessarily the same problem causing it. If the others would post back with additional information then maybe we could see if anyone has figured anything out.


30 Year Tech, You've been working on these machines for decades. In your opinion, do you think an 8 1/2 year old Kohler twin engine that's used weekly for personal use and is well maintained has passed its peak years of efficiency? This engine is tough and has tons of torque. It uses no oil and I just replaced its sparkplugs for the first time. One guy told me he likes Honda twin engines better, but I'll bet they cost a lot more than a Kohler engine.


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## 30yearTech (Sep 14, 2006)

Kohler is as good as any, I like Kawasaki engines myself. While Honda engines are very good, I would not rate them any better then a Kohler, and most engines with reasonable care will last a good long time. You should have plenty of life left in your engine, it just needs whatever is wrong fixed. I know it can be frustrating, but hopefully a good tech will come out and get it figured out for you. It sounds like it still has some kind of fuel delivery issue to me, but without looking at it, who knows for sure.

Best of Luck....


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## goball (Sep 25, 2006)

*Kohler*

Walker,

Considering the post in this thread, you've been suffering far too long. Good thing you aren't paying the labor. This might be a dumb suggestion but it could be, as mentioned earlier, an electrical problem caused by in intermittent switch. Not sure what safety switches you have but typically there are three, seat (yu have to be sitting on the seat to keep it running), a switch connected to the deck so the engine won't start with the deck engaged and a third probably associated with the brake or clutch. There might be one more being an oil level or pressure switch in the engine oil system. All these probably de-energize the fuel solenoid threaded into the bowl of the carburetor. If the solenoid de-energizes, the fuel to the main jet is blocked off and the engine dies even though the ignition is still on. Two ways to check the solenoid action: one - connect a voltmeter to the solenoid and watch that it has a constant 12 volts to it while the ignition is on or you can connect a constant 12 volt source from the battery to the solenoid (for testing only). If the engine runs well constantly with the 12 volt source or it drops of intermittently while the engine is running, bets are you have a safety switch problem. Just a thought and good luck. You deserve better. Gogall


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## 30yearTech (Sep 14, 2006)

Safety interlock switches do not operate the fuel solenoid. The purpose of the solenoid is to prevent after fire in the muffler when the engine is shut down. The safety switches only interlock the ignition system, and intermediately shut down the engine when tripped.


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## walker1 (Apr 27, 2009)

goball said:


> Walker,
> 
> Considering the post in this thread, you've been suffering far too long. Good thing you aren't paying the labor. This might be a dumb suggestion but it could be, as mentioned earlier, an electrical problem caused by in intermittent switch. Not sure what safety switches you have but typically there are three, seat (yu have to be sitting on the seat to keep it running), a switch connected to the deck so the engine won't start with the deck engaged and a third probably associated with the brake or clutch. There might be one more being an oil level or pressure switch in the engine oil system. All these probably de-energize the fuel solenoid threaded into the bowl of the carburetor. If the solenoid de-energizes, the fuel to the main jet is blocked off and the engine dies even though the ignition is still on. Two ways to check the solenoid action: one - connect a voltmeter to the solenoid and watch that it has a constant 12 volts to it while the ignition is on or you can connect a constant 12 volt source from the battery to the solenoid (for testing only). If the engine runs well constantly with the 12 volt source or it drops of intermittently while the engine is running, bets are you have a safety switch problem. Just a thought and good luck. You deserve better. Gogall


Gogall, Actually, I figure my time per hr. is worth at least $30 or so as I take care of our country compound, vehicles, lawn/landscape maint., and I even vacumn and do all the shopping. Oh, I forgot- I also am very good with working on our computers and electronics.

I gave the Kohler shop guy $30 for his time & blowing out the carb & fuel tank. He didn't want to take the money, but he was a nice guy. I will keep his card for future reference. It's too bad he couldn't pick up the tractor as he doesn't have a vehicle or trailer either.

He did check the solenoid @ his shop using a 12 volt battery. He also told me if you turn the ignition key to thr right once & listen you'll hear a clicking sound and that's the solenoid engaging.

I hope Sears can find the problem and it isn't that solenoid as it's 1 expensive little part. I haven't figured out why the carb needs one. Kohler says some of their carbs have them and some don't. Go figure.:thumbsup:


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## walker1 (Apr 27, 2009)

30yearTech said:


> Safety interlock switches do not operate the fuel solenoid. The purpose of the solenoid is to prevent after fire in the muffler when the engine is shut down. The safety switches only interlock the ignition system, and intermediately shut down the engine when tripped.


30yearTech, Can you tell me exactly where in the solenoid is the plunger you were referencing? I will have a look @ it this weekend. You said I could try taking the plunger out & running the tractor. What does the plunger do & how could it affect the engine's driveability? Thanks. Walker:thumbsup:


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## hd4ou (Aug 25, 2009)

im certainly not 30yr but what i do is remove the solenoid pull the plunger out as far as i can and just cut it off. does not affect the driveabilty at all. if you do this though make sure you idle her down first and let her cool for a min or two.


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## 30yearTech (Sep 14, 2006)

The fuel solenoid screws into the bottom of the carburetor. It's purpose is to stop the flow of fuel into the main jet of the carburetor when the engine is shut down. This prevents a build up of unburned fuel in the muffler that may ignite if the muffler is hot enough. 

All the Kohler engines I have ever worked on, you can take apart the fuel solenoid for cleaning. some have the main jet screwed into the top and some just have the plunger extending up out of the solenoid. If yours has the main jet screwed into the top, then remove the main jet and shake the solenoid upside down and the plunger and spring will fall out. Reinstall the main jet without the plunger and put the solenoid back in the carburetor and give it a try, you don't have to plug it back in. If your solenoid just has the plunger sticking out, then grab the plunger with a pair of pliers and pull it out, there willl also be a small spring underneath the plunger that will come out also. Reinstall the solenoid and see if your problem is solved. 

You can run your engine without the solenoid, it won't damage it. You should however let your engine idle for a minute before shutting it down to help prevent the after fire in your muffler. If running it without the plunger does not make any difference, then you can safely assume that is not your problem. Save the plunger and spring so you can reassemble your solenoid if you decide you want it back.

Best of Luck.... :thumbsup:


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## walker1 (Apr 27, 2009)

30yearTech said:


> The fuel solenoid screws into the bottom of the carburetor. It's purpose is to stop the flow of fuel into the main jet of the carburetor when the engine is shut down. This prevents a build up of unburned fuel in the muffler that may ignite if the muffler is hot enough.
> 
> All the Kohler engines I have ever worked on, you can take apart the fuel solenoid for cleaning. some have the main jet screwed into the top and some just have the plunger extending up out of the solenoid. If yours has the main jet screwed into the top, then remove the main jet and shake the solenoid upside down and the plunger and spring will fall out. Reinstall the main jet without the plunger and put the solenoid back in the carburetor and give it a try, you don't have to plug it back in. If your solenoid just has the plunger sticking out, then grab the plunger with a pair of pliers and pull it out, there willl also be a small spring underneath the plunger that will come out also. Reinstall the solenoid and see if your problem is solved.
> 
> ...


Hello, 

The verdict is in. The Sears guy came and the tractor wouldn't start. He determined that fuel got to the carburetor with the line off. He then took a brand-new carb out of his truck after telling me how much it would cost and bolted it on.

Well, his carb didn't run any better. He reinstalled my carb, called Sears, and talked with somebody more knowledgeable than he about the problem. He was told to check the fuel line behind the air cleaner plate and look for any restriction in the fuel line. With the plate off the engine started and ran perfectly. He drove the tractor around the yard for about five minutes with the blades on and off and it ran perfect.

The problem was twofold. First, I definitely had debris in the carb initially from the gas. That problem was resolved, but I had no idea the fuel line could get pinched a little from the plate pushing against it. The answer is to make sure the fuel line isn't pinched and don't tighten the carb nuts too tight.

My cost was $107 for Sears and they warranty the "fix" for 90 days. If the tractor starts acting up again there will be no charge for a technician to come back. That's very acceptable to me. I learned something new today about fuel lines and how touchy they can be. I guess this was the best way overall because of truck rentals, etc. Thanks for your help as always.:thumbsup:


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## 30yearTech (Sep 14, 2006)

It's a good thing the fuel line got pinched when he put the new carburetor on. Otherwise they would have sold you a new carburetor, which wasn't the problem and you would have never realized it.

Anyways, it great that you got it going again and it did not cost you a new carburetor.


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## walker1 (Apr 27, 2009)

30yearTech said:


> It's a good thing the fuel line got pinched when he put the new carburetor on. Otherwise they would have sold you a new carburetor, which wasn't the problem and you would have never realized it.
> 
> Anyways, it great that you got it going again and it did not cost you a new carburetor.


Yes, Especially @ the price- Total for labor, trip charge, and carb= $488.50. The carb price was around $270.00.


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