I tried to shoot it out with my air gun but that nut doesnt want to come loose any one have a suggestion. I am doing a rebuild but that dame nut wont come off. let me know thanks.

 

3-4ft breaker bar.

 

You need a pretty powerfull gun to take it off. I use a Matco 1/2" impact gun with 700 lb/ft reverse torque. If its an original mazda motor, It can be a ****. Try heating the bolt with a torch or secure the flywheel with a flywheel holder and use a big breaker bar.