Question: My go cart will start up and run but after running for about a minute is shuts off. Why?
There are a couple of reasons why an engine will start up and then just quit they are:
– Carburetor Float Problem
– Bad Valve, either exhaust or intake, typically exhaust.
The latter (bad valve) is the most common, especially if the go kart has been used quite often. The constant acceleration causes the engine to not cool down properly and burn up the exhaust valve.
The reason why it occurs later in the running cycle, is because the “leak” opens itself up with heat. Once the leak is open it gets to be real hard to keep the engine running.
A breif compression check when it quits will answer the question.
If the compression is still there you should feel it in the starter rope when you turn the engine over. If the compression is low, the engine will just “flump” over with little resistance.
Valves can be easily replaced. Typically the valve seat is not damage (because it is a harder material) but the valve will be worn out.
A new valve, some lapping compound can do wonders on a weak compression engine. Be sure to get the correct valve clearance between the lifter and the bottom of the valve. Also make sure the valve bottom is square, at not ground at some goofy angle.
You will be able to tell immediately that you have solved the problem because of the snappy compression and the quick starting engine. Also you will get better power too!