lt 15 Kohler hot starting

[alanh]

I`ve been dealing with this for a while now and haven`t come up with anything. The motor starts and runs fine but if I shut it off for some reason, (change a blade, go get another log, etc.) after its been working a while it won`t start, it spins over and has spark but won`t fire no matter how much choke/throttle jiggling I do. If I take off the air filter and dump some gas down the carb and then start it like its flooded (cuz it is) it`ll start. Any ideas?

[SawyerTed]

This where I would start.

Fuel filter replaced
Clean the tank.  I've had things float around in a fuel tank and only clog the outlet when it's running. A wasp and a maple seed are two I remember.
Check the fuel lines to be sure they are clear.  Any gas with ethanol can ruin some fuel lines.  They look fine on the outside but the inner line can collapse. Suction from the fuel pump / efi or carb can pull that inner fuel line liner shut.
Does your Kohler have the fuel pump on the valve cover?  If so make sure it is still pumping when the engine is hot.
 
It just me but I would go after all these before getting into the carb or efi.

[Haleiwa]

Sounds like a stretched exhaust valve to me.  The valve can barely close enough to make compression; once hot it leaves a gap so the engine won't start.  An engine can run with a slight compression loss, but it won't start.  Check the lash first,if that is correct, you can try filing thirty thousandths off the end of the valve stem.  If that doesn't work, replace the valve and lap the seat.

[MartyParsons]

Hello,
  How many hp? 13 15 18 19 or 25?
I would check the fuel solenoid on the carb and see if it may be sticking. depending on the engine.  It would have hydraulic valve lifters. 10W30 engine oil?
Depending on year. The fuel tank location was an issue the fuel pump would not deliver fuel this was only for a few mills WM relocated the tank. I am not sure if I remember the distance the pump would carry fuel. Connector seal on the red gas tanks could also need checked. Again not sure what engine or year your LT15 is .
Marty

[UN Hooker]

   Near the oil filter, if there is a sensor with a wire attached to it, pull the wire off and see if that makes a difference .
                                    UN

[alanh]

Marty, its the 13, 2005 era, I`m not sure what oil I used last...but 10/30 is usually whats in the shop

[mike_belben]

Is the spark bright blue or weak and barely visible?  Failing ignition can give some hot start grief. 

A flooded engine doesnt want fuel poured in it.   It wants no fuel and a wide open throttle for maximum airflow to sweep the flood condition away and dry the plug out.  Been working for me the past 30 years consistently.

[Even saying that is scary.  I still feel like a frusterated 8 year old kicking his heart out on a junky quadsport.  Where did the time go?]

[alanh]

spark looks ok, I`m aware of the flooded engine starting procedure, I`m saying the only way it`ll start is to pour fuel into and then crank it over while holding the throttle open. 

[Tramp Bushler]

Sounds like some kind of vapor lock. And or the fuel pump system is letting the fuel drain off. 
 The 17 horse Kohler on my Mighty Mite needed fuel dumped into the carb when I first started it up. It holds its prime now. But then I haven't gotten it up to full operating temp from sawing a wide cut yet. 

[mike_belben]

My bad alan, i misinterpretted you. Sorry.

[firefighter ontheside]

I have similar trouble with my LT15 with 15 horse Kohler.  It has an automatic choke that doesn't work right.  I have to stick my hand under the air cleaner and manually move the spring loaded choke.  I replaced the spark plug and it was better today, but I still had one instance where it was hard to start.  Seems to be worst when the engine is still warm, but not hot or cold.