1990 GQ Patrol RB30 Carby No Go

Hey Guys i seem to be having trouble with my engine not wanting to fire up and after doing the initial checks I'm a bit buggered.
* it has fuel going in to the carby but i took this off and cleaned this out any way, also replaced the fuel filter.
* it has spark at #1 plug.
*dizzy is rotating.
* hooked up timing light But no light flashing on timing light ( brand new out of box unless bulb was already blown.)
have now run battery to low on charge ATM.
even took off the lead off the coil and it was producing spark.
??? Have I missed any thing that i should look at ??
could the timing belt have slipped?
if a cant figure it out ill take it to mechanic for him to look at.
Cheers Dink
Thanks in Advance.
Also this was on the Base of carby between inlet manifold but the plug was off would this affect the starting of it??