If you can narrow down your problem further using the diagnostic tests in the above posts and post any questionable results you'll have better luck getting an answer. Some of us can be a little harsh.
Usually they have a bit more trouble starting when they're cold, generally start instantly when motor is warmed up. Maybe try pumping the primer bulb a few times when motor is hot and give that a try. Are your spark plugs good and clean? Good Luck and let us know what you find!
ok i got the engine back from the shop & they did a service ,change plugs & oils ,the usual, they tell me the plugs where oily & the fuel mixture was a bit rich,which they tuned it better, but they couldnt find a fault, i guess i will find out this weekend.
If this thing runs fine but has trouble starting after getting warmed up then you or the shop will have to do some testing in those conditions, while the problem is occurring.
Since you will not post a model # no one even knows if this thing has carbs, or injectors
