You may have run into this or you may run into this where you are riding your go kart on a bumpy, gravely driveway and suddenly the go kart stops running properly. It just up and quits.
“Why would the go kart suddenly quit?” Is the question in your mind and “What would cause the go kart engine to stop running, since obviously nothing touched it?”
What you will run into is that when you are riding a go kart on a rough surface the engine will be bounced up and down and in this ” bouncing up and down” the carburetor is jostled up and down. The carburetor inside has a bowl, and inside the bowl is a float that floats literally on gasoline. When the go kart is bounced up and down the float can be bounced up or down and typically will jammed in the needle valve in its seat. It literally jams the needle valve into its seat and the only way to get it released is to jostle it again.
The jostling effect usually comes when you start up the engine in choke it because that’s all that will that will cause the engine to run. It will run almost indefinitely and that’s a symptom that you jammed needle valve. Typically we will frantically start adjusting needle jets trying to get things to work better, just so we can limp home. We will discover however that it is probably the float inside the carburetor causing all the grief.
If this continues to be a problem you have an alternative plan, and that is to buy a new diaphragm carburetor, or find a new carburetor that has no float in it. You see the float is designed to regulate the gas requirements for the engine. A “floated” carburetor is designed to run on a level surface not a surface that is a hill or surface that is constantly being bumped. The diaphragm carburetor however is used on things that are bounced around a lot and change angle positions a lot. For instance they are found in weed wackers and chainsaws. The best way to find a diaphragm carburetor is to go to a local small engine repair store and purchase yourself a diaphragm carburetor that will meet the CFM requirements for your engine. Also you can shop on eBay and find some second-hand used diaphragm carburetors. You need to make sure that you get the right size carburetor otherwise you will be starving your engine for its gas requirement.
And finally the engines that are most susceptible to this particular ailment are engines I have bowl-float combinations. Some of the manufacturers have come up with rubber tipped needle valves which help solve this problem, however you will discover that even going up hills can be an issue so in case you’re wondering why your go kart is quitting after you’ve been running it over bumps and or going up hills, it is because of this float needle jamming issue.