Does that electric connection run a solenoid that stops the gas flow when shut off ?????
If not what does it do ??

 

KATT yes you are right it does shut the fuel off when the key is in the off position but the fuel is stopped at the point it enters the jet area but does not stop fuel from entering into the fuel bowl thru the float needle seat & thus does not prevent the fuel from overflowing the fuel bowl in the event the float needle & seat leaks.

 

It could be boiling the fuel in the bowl.

 

Check and see for the float is cracked or needs height adjustment

 

Thanks megalosdog for the reply it is added to my list of things to check in the process of elimination that I am going to do in a check list fashion so that I can determine which one actually fixes problem & I will post the cure here so others will have answers to the same problem that is not just specific to me.

 

In Katt's pic there is a heat shield missing. It covers the whole front of the motor and directs the hot air from the exhaust away from the front of the motor.

 

Thanks rayjay that is correct but the picture cannot be taken with the heat shield in place
but for those that do not work on these models may need to know that the heat shield is very important for the motors operation to reduce the heat build up in the carb area, and needs to be in place for operation purpose.

 

Since we are being technical it is called....... M114313 air duct. The PO took it off to fix what he thought was a bad fuel pump and never gave it to nephew @ pick-up time so......$30 bucks later from e-bay I now have one.
I still need to test the fuel pump but the PO supplied NO fuel line...... 1/4 " ????? since the PO was running it with a plastic jar strapped to the inside of the hood by gravity feed ...:sidelaugh only it's NOT funnyisgus:

 

I know it tested okay at 10 psi but it still sounds like an issue with the either the float, needle, or seat.

 

My 345 will burp a little fuel out of that top vent on the carb if you shut it off hot without letting it idle for a minute,but if you let it idle for a minute it does not do it.Been that way since new.

 

Same problem here as well. I've got a 1996 LX188. Motor ran great but, I recently replaced the carb because mine was overflowing fuel immediately after shutdown. Now the replacement carb seems to be burping a small amount of what appears to be fuel too. The original carb only had a short rubber elbow that dumped quite a bit of fuel onto the fuel pump. With the new carb I ran a vent line down through the chassis. And sure enough within a minute or so after shutdown I still get a few drips of fuel/vapor on the ground. Nowhere near the amount as the old carb did but still unsettling. Some of the local shops think it's water vapor boiling off from the ethanol(10%) in our pump fuel. I'm not sure what the answer is but it makes me uneasy anytime I see fuel hitting the garage floor.

 

The lx188 fuel overflow problem is fixed the problem resulted from the ethanol in the fuel damaged the rubber float needel seat & it would test ok to 10 psi cold but when hot it would swell & leak fuel into the bowl & overflow out the top overflow hose. a new seat for the needle & new needle solved the problem for now untill the ethanol messes it up again.

 

My old carb had a steel tipped needle as well as the replacement needle that my JD dealer sold me. Both leaked immediately, hence the new carb. Now I get only a few drops off the vent tube and the carb is only 3 weeks old. I'm dumbfounded by this. The new carb does however have the rubber tipped needle in it. Do you have a part number for the needle seat? The dealer told me it was NOT replaceable? I can't believe Mikuni would build a carb that wouldn't have a replaceable seat.