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johnnymag3

runs fine then ....pop pow.flames..stall cough ...STILL AN ISSUE

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johnnymag3

Ok Guys, I have been through everything on this 12 HP kohler......how can it run and idle fine for 5-6 minutes, sometimes 20 minutes........ then no start situation occurs......pop....cough...pow....flames out of the carb....pop....pow   .

 

Should I just get  a new carb? this one is doing weird stuff, and its spotless inside and out.!! It does not have the main jet screw as I though before

               . I took it apart, cleaned everything, and it is still a MESS>>>

 

Thanks as always, John

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Daddy Don

Check your point gap. I had to set mine at .18 to get it to quit doing this c-111 14hp kohler 

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gwest_ca

See this is a Magnum. If an older model with battery ignition a bad condenser will yield your results.

Have you removed the fuel tank and cleaned it out? May have something like a leaf or piece of paper getting sucked to the intake screen when running. Shut it off and it floats away from the screen. Have seen it happen.

 

Garry

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BOB ELLISON

I'm no expert on these but it sounds like it's out of timing or valves sticking. I think you can check timing through a hole in front of the fly wheel cover. Check the key in the flywheel to see if it's ok. Reset the points . Others will help

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johnnymag3

There are no points on this Magnum, and now it wont start......just pops,and back fires......then all of a sudden it will start and run fine.......25 seconds later it acts up again. Im going crazy here trying to figure this out.

 

Gas tank is clean....:blink:

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953 nut

I had similar symptoms once that turned out to be an excessive carbon build up in the cylinder. When it totally quit and would only backfire from the carburetor I pulled the head and found a chunk of carbon had dislodged itself and was holding the intake valve part way open.

Made a scraper out of some scrap oak and cleaned it all up, no problems after that.

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johnnymag3

I started the tractor after work today @ 1 PM.......its been running fine since then on idle,half throttle, full throttle. Im afraid to turn it off !!!!Runs smooth as silk.

               I just dont get it

 

made no changes to anything, just kept trying to start, pop    pow     flames out of the carb....then vroooooooooooooom its been running ever since !!!

 

I guess that eliminates some of the ideas?    OR DOES IT ?

 

I love my Horses.........its a sickness I believe, but im glad I have the right color in my stable !!!!

 

Gonna turn it off soon, then let it cool. I will try to start it in a few hours....FINGERS CROSSED

 

John

 

thanks for all of the suggestions, helps me keep my sanity

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johnnymag3

Will let you know what and IF something happens when I try the refire

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johnnymag3

so it started, unwillingly, but it did run

Took 3-4 angry pops and backfires to go but then it ran ok..when it coughs it sprays fuel out of the carb, like somebody sneezing !

 

when its running is purrs like a kitten

 

Cant quite figure this one out?

 

John

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pfrederi

Have you checked the float level???  11/64"

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953 nut
1 hour ago, johnnymag3 said:

when it coughs it sprays fuel out of the carb, like somebody sneezing !

Think about it! What would cause pressure (cough) to come out of the carburetor? An intake valve being part way open while on the compression stroke would do this. The rapid air movement out of the carburetor is causing a venturi effect delivering atomized fuel to the outside just like it would on intake.

Now think of what could cause this to happen intermittently and then clear up?  See post #6.

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johnnymag3

So.....I guess its take off the head, as you mentioned in post #6...can I borrow the oak stick to clean it off?

 

or could it be a tight valve guide?

 

Hmmmm

 

Runs so well when it does start.....At least it has a name now     SNAP CRACKLE POP.....Thats my name for this little devil of a tractor.

  • Haha 1

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boovuc

The back firing and coughing is an engine that could be leaning out on fuel. The fact it's intermittent can be a float or impeded fuel source. You should do the easiest and most common fixes FIRST before opening Pandora's box.

Before tearing that engine open:

 

Check the float gap as mentioned above or better yet, buy a carb kit and do that carb over. Make sure the butterfly bushings aren't wobbling around and adding a 2nd issue to another. Make sure every orifice and port is opened up all the way.

You didn't say if you opened the carb or even took the bowl off. Well over 50% of the issues you are seeing can be fixed at the carb or back to the fuel tank.

Make sure the bolts holding the carb to the intake of the engine are not loose. If you don't want to rebuild the carb at least take the bowl off, clean it up along with the float and needle valve on it. Then, using a screw driver, gently turn the main jet on your carb in until it just starts to get snug counting how many rotations you turned it. Then take it all the way out, clean up the needle valve and spray the crap out of the orifice before putting it in gently all the way then turning it out to the original setting you counted earlier. Make sure you spray carb cleaner into the fuel intake opening as well.

Check your air filter! Is it old and plugged up? Run it sitting still with no debris around it without the air cleaner in. See if it helps or clears the issue. Doubtful but a plugged air filter and a dirty carb and bad throttle plate bushings, etc all can add to an issue).

 

If tidying up the carb didn't help, get a small plastic gas tank off of a small engine. It only needs to hold a little gasoline. Put a shutoff valve on it and a filter if you wish and hang it above the engine or get someone to hold it higher than the engine. make sure you shut off the fuel valve from your tractor's fuel tank before proceeding! Disconnect the fuel line from the carb as it is now! Hook the little gravity fed fuel tank directly to the carb intake as you would from your tractor's fuel pump and start it up. This will tell you if you have a weak diaphragm pump, obstructions in your own fuel lines or vacuuming of your fuel tank "IF" the issues disappear.

If doing these simple things first don't help, then move on to the others.

If you do have a valve obstruction, if you can get it running as you say you can on occasion, spray Seafoam into the carb intake at medium to wide open throttle and try break up any carbon that may be on the top end of that engine or in the valve seat. (Yes it will smoke like crazy).

Again, not knocking anyone's suggestions but do the simple stuff first and eliminate the common issues first before delving deeper.

 

 

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johnnymag3

Hi and thanks for all fo the suggestions.....I have done everything you have mentioned, and I am going to take off the head. The Carb is clean, I had it apart 3 times....see other posts. I have a new fuel filter, mixture screws are set perfect, tank is clean, new gas installed All new gas lines, fuel delivery is perfect. Fuel pump tested on and off the engine, new spark plug, gapped @ .025.

..11/64 for my float in carb....there is really nothing else to look at.......Has to be an open intake vale, or at least partially in order for it to shoot flames on the combustion cycle,,,,,,,,no other explanation for it.When its trying to start, as I have had the air cleaner off this entire time, it blows fuel out of the carb. 

 

Ran Seafoam, Marvel, you name it.....no change. The carb bowl is spotless, as are all of the needle valves.

 

THANKS!!!!!    John:)

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johnnymag3

My Money is 953 NUT !!!!!!!

junk in the intake valve...........or on it.....Maybe even varnished stem keeping it from moving fully to the closed position.

when it starts, it runs excellent.

 

John:D

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johnnymag3

Remember, it sat for three years, and has only 246 Hours on it.............so carb wear is near minimal

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wallfish
3 hours ago, johnnymag3 said:

My Money is 953 NUT !!!!!!!

junk in the intake valve...........or on it

especially if it's breathing fire out of the carb.

 

On 7/21/2018 at 2:41 PM, johnnymag3 said:

pop    pow     flames out of the carb

Don't remember reading this on the other thread

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johnnymag3

its so hard to remember all of the details, but the scenario is still the same.........

 

Sorry

 

Was going to pull it apart tonight, but life got in my way

 

UGH.....

 

john

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johnnymag3

Wallfish, are you on the same page as 953 NUT?

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johnnymag3

Do I tear this low hour engine apart?

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wallfish
On 7/23/2018 at 7:47 PM, johnnymag3 said:

Wallfish, are you on the same page as 953 NUT?

I'm no engine expert but breathing fire out of the carb indicates intake valve to me. :twocents-02cents:

 

 

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johnnymag3

just ordered valve spring compressor, head gasket, and im on the move!!!! Taking off the head

 

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johnnymag3

So l pulled the head.....Spotless inside

      so then I tried to check the intake valve clearance setting

.000

set it a .009, put engine together, runs like new

what causes this situation

how can it change?

when I adjusted, seemed like there was plenty of resistance in the lifter, and adjuster

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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johnnymag3

so what do I name the tractor now? It starts with a half turn of the key.......no more snap ......crackle .....pop......hmmmmmm

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johnnymag3

246 ?    the hours on the tractor.....   NO 

 

   how about BIG PAIN IN THE A#$#

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