if it was sitting for a long time the low and high needles may be clogged. You need to hook up a line into some alcohol, crank it to run the alcohol through the engine. not trying to ignite it, NO GLOW PLUG OR GLOW IGNITER ATTACHED!!! do that for a few minutes. this will help to eat away at any gunky deposits. Then allow the alcohol to dry away, make sure you then put about 5 or 6 drops of afterrun oil in the cylinder to lubricate it. then hook up the fuel line again, prime it and try again. Sometimes a little deposit removal is what you need. Also check your fuel lines to be sure they have not cracked and need replacing.