I have my Matrix tuned at the factory standards. However, when I start it it will run for about 20 to 30 seconds and cut off. I'm not sure of what to do or what causing it. Could someone help me please.

does it idle for 20to30 or can you only drive it for 20-30?

It will idle for about 20-30 seconds and if I keep the igniter on the plug it will run even longer.

Did you try changing the glow plug?

usually if it dies, it means the engine loaded up with fuel. you could try leaning the low end a little 1/12th turn at a time and see if this will help your idle issue. Also the engines shouldnt idle forever, and i have had quite a few people tell me that 20to 30 seconds is all you want the engine to idle before it dies.

Should it be a turn in or out on the low needle?