Axial 28 problem..
 

I got a used axial 28 ,I don't know how many gallons thru it...I'm tryin to fire it up for the 1st time today but it won't prime.the nitro won't go in the engine..I tried covering the exhaust while on roto start still no go..I tried the primer on tank and nothing..can someone pls help..the tank has no leaks.