C-120 carburator leaking gas out front of carb

[Sailman 1,299]

Tried to search for solutions here but no luck so asking the Kohler experts here for advice. C-120 was starting and running fine. Took it out to mow yesterday and stopped running. Ran it out of gas. Oooops...Put gas in the tank and was hard to get it started. Primed the fuel pump and sprayed starting fluid into the carb. Got it to run BUT then it started leaking gas out the front of the carb. Assumed it was stuck float or needle valve so I removed carb, replaced needle valve seat, needle valve and float pin (had some new parts left over from rebuild kit) and made sure the float was level. Back on the tractor same problem. If I leave the bowl off, the float and needle valve work fine with me raising and lowering the float with my finger. Put the bowl back on and gas starts running out as soon as bowl fills! At a total loss to figure out what I am missing....Any body here know what it could be???

[ZXT 2,401]

Did the float have any liquid in it that you could tell? 

 

It would have to be a coincidence as running it out of gas wouldn't cause the float to sink, but since you say the needle and seat function as intended with the bowl off, there aren't many other options. Did you adjust the float or leave it as it was? You might've set it too high.  

[Sailman 1,299]

Float was perfectly dry, no gas getting in. Float is set perfectly level....

[Sailman 1,299]

I had actually set the float lower first time by bending the tab more open. Did not stop the leak so I adjusted it back to level. Same issue.

[ZXT 2,401]

2 minutes ago, Sailman said:

Float was perfectly dry, no gas getting in. Float is set perfectly level....

The only thing that can cause a carb to overflow like that is a leaky needle/seat.

 

Are you running an electric pump? I assume a mechanical since you mentioned priming it.

[Sailman 1,299]

original mechanical pump. The flow from the tank through the pump stops when I activate the float and needle valve with bowl off so I don't think its needle valve or seat.

[ZXT 2,401]

20 minutes ago, Sailman said:

original mechanical pump. The flow from the tank through the pump stops when I activate the float and needle valve with bowl off so I don't think its needle valve or seat.

There's something obviously not right.. Maybe the float is binding on the bowl somehow? If the needle and seat were sealing, there would be no way for fuel to get through to leak through the front of the carb.

[rmaynard 15,919]

In all my time servicing Kohler engines, a leaking carburetor has almost always been a float valve problem. When replacing a valve and seat, be sure that they are a matched pair. Also, you didn't mention that you replaced the rubber gasket and splash shield. An old, worn splash shield can sometimes keep the float from raising completely to the closed position.

Edited September 7, 2020 by rmaynard

[ET160 30]

I agree with the float idea.  I had a similar issue with my B-80, to find that the float had a hole in it and was filled with gas (no longer floating).

[tunahead72 2,518]

1 hour ago, rmaynard said:

... Also, you didn't mention that you replaced the rubber gasket and splash shield. An old, worn splash shield can sometimes keep the float from raising completely to the closed position.

 

After reading everything you've tried, I'm with Bob on checking the gaskets.

 

Also, was your new float pin knurled on one end?  I'm no expert, but I understand that style can sometimes hang up and interfere with proper movement of the float.

 

[Ed Kennell 40,494]

Bowl off it seals, bowl on it leaks.    I go with Bob,  it has to be splash shield interfering with the float operation.     Leave the splash shield out and try it.

[pfrederi 18,334]

Always wondered about the splash shield.  Kohler carbs used it Walbro for same engines did not?????

[rmaynard 15,919]

 

2 hours ago, pfrederi said:

Always wondered about the splash shield.  Kohler carbs used it Walbro for same engines did not?????

I had an 857 with a K-181. It had a carburetor that I left the splash shield out. It worked fine until I got on some very bumpy terrain. The engine kept sputtering and would flood out. After installing a splash shield, the problem was corrected. I guess they do serve a purpose.

Edited September 7, 2020 by rmaynard

[Sailman 1,299]

Sounds like the splash shield. I didn't have a new one and the last carb rebuild kit I got from Brian @ 76c12091520h had the leftover needle valve, seat and float pin (not knurled). Brian had told me you did not need the splash shield so I had left it out when I put the carb back together since it was old BUT without it the the bowl gasket (old) was leaking around the bowl so I put the old splash shield back in...stopped the bowl leaking BUT still and having the gas overflow from front of carb issue. I have some more carb kits coming from I save tractors so best to just put the new gaskets in and see if that solves the issue. Don't know what else it could be. Thanks for all the input!!!

[Sailman 1,299]

Well I resolved my issue and wanted to let all know for 2 reasons;

1. I appreciate everyone who sent suggestions and advice and want you all to know my situation is resolved as per your comments.

2. So the next poor sucker who is as much of a moron as I am....won't make the same mistake!

I received the carb rebuild kit and put the 2 new gaskets in the carb and....gas still leaking out the front. Removed it for about the 6th or 7th time and stood there shaking my head in exasperation.... which led to my shaking the float....duh...gas in the float! It felt so light before I didn't even consider that possibility. Drilled a hole, shook out the gas, soldered the hole (will still plan to get a new float) and voilla!!

Now you know why...when the experts on here tell me I could rebuild the engine if needed...I have that deer in the headlights response....... Its always the simple things that get me!!!

Oh well...I am now intimately familiar with the Kohler carbs!!!

Thanks for all your help!

[ZXT 2,401]

19 hours ago, Sailman said:

Well I resolved my issue and wanted to let all know for 2 reasons;

1. I appreciate everyone who sent suggestions and advice and want you all to know my situation is resolved as per your comments.

2. So the next poor sucker who is as much of a moron as I am....won't make the same mistake!

I received the carb rebuild kit and put the 2 new gaskets in the carb and....gas still leaking out the front. Removed it for about the 6th or 7th time and stood there shaking my head in exasperation.... which led to my shaking the float....duh...gas in the float! It felt so light before I didn't even consider that possibility. Drilled a hole, shook out the gas, soldered the hole (will still plan to get a new float) and voilla!!

Now you know why...when the experts on here tell me I could rebuild the engine if needed...I have that deer in the headlights response....... Its always the simple things that get me!!!

Oh well...I am now intimately familiar with the Kohler carbs!!!

Thanks for all your help!

Glad you got it fixed! I've had one do the same thing recently, which was why that was my first suggestion. It doesn't take much fuel in it at all to upset the buoyancy. The one I dealt with had just enough in it that you could hear it when you shook it, but not really enough to affect the weight that I could tell. 

 

Were you able to find the hole/crack that allowed the fuel in? If not, you'll probably be back in the same boat before long. When checking for cracks, spray brake parts cleaner on it and watch it dry. Everything on the surface will evaporate, but if there's a crack that it ran down in, it will still appear wet.