well it now sounds like you have none or indeed very little oil in the head . It should idle if the ignition amp is working correctly. Not starting an investigation but it sounds like you had cold and even damp storage . If you have good oil level your now going to have to check reasons for that blockage . But don't let it run with no oil in the head take the cover off and have a look for fresh warm oil . It sounds like it needs an in-depth re-commissioning .