I sounds like you could have an airlock in the fuel system.

I know you've tried priming it with the bulb but for some reason that doesn't always work.

You could try the brake / clutch cleaner trick to see if it starts.

Spray small bursts of brake cleaner into the inlet manifold when trying to start the car, this often gets them to fire & start, if it starts keep it running to bleed any air from the fuel system.

Give it a go and see what happens.