My 450ES won't stay running. It had been sitting for several months, so I drained the tank and carb bowl, filled up with fresh gas, replaced the spark plug and checked the air cleaner which is clean. Now when I start it, it will run with the choke pulled all the way out (and has relatively good throttle response), but if the choke vibrates in, even a little, it dies. I have let it idle for about 15-20 minutes to warm up but that does not help. I have tried adjusting the idle speed screw (the one with the plastic **** on it) and can get it to idle up, but it still will not run if the choke is pushed in. I did manage to get it to stay running by reving it up, then pushing in the choke, but it runs very rough (missing and popping) and will not stay running if I release the throttle. The air temp is around 40 degrees here and I am not at high altitude. The machine is stock and has relative low hours on it.


Any help will be greatly appreciated.

 

The pilot jet is plugged up . Youll need to drop the float bowl and remove the pilot jet and clean it out.As the gas in the float bowl evaporates, its refilled, because the gas tank valve was left to on. The constant evaporation and refilling, causes the sediment to build up on the small holes in the carb. The pilot jet is the smallest, and the first to plug up.
Pulling the 'choke' on, is actually opening a starter jet, this is the gas your motor is running on. When you turn the choke off...the gas flow stops.
The way to keep this from happening again, is turn the gas tank valve to off, and drain the float bowl...if you know the motor will sit with out being started for more than a week.

 

You are right, that is what the problem was. I had actually already pulled the carb. again and removed both jets. The only thing that I found that was gummed up was the pilot jet, but I gave everything else a good cleaning anyway. It is running like it should now. Thanks for the help.

 

welcome to the forums.

 

Thanks!