Wont eject round after firing

take it to a gunsmith

Did you clean the gas tube and rod ?

It takes about 250 rounds to break in a gun. Try some hotter ammo and see if the problem disappears, if so, call Marlin and ask them for their solution if you want to keep using Federal, you might want to try some Remington standard velocity target, it is very accurate in most guns.
I would shoot it for at least 500 rounds and clean it from powder debris in chamber and receiver bolt and trigger group and try it again, however don't hesitate to get a hold of Marlin, they are nice folks.

Various nailers will fire on their own when connected to air if the orings have become hard or worn and internal trigger valve parts worn-out (mostly Dewalt and P/C). You could buy an oring kit or purchase trigger valve seperately. Replacing trigger valve and lubing the headvalve with white grease will most likely solve the problem. After repairing the gun, be sure to remove the nails from the mag after each use to prevent possible discharge of nail. Good luck

i found this happening to me and i oiled (light oil like 3 in 1) the driver (hammer) in the tip. that way it could retract and drive the next brad.

there is a lever under the barrel and it is probably worn beyond function or broken off all you need to do is disassemble the gun and replace it. ( get yourself some good brass punches)

make sure your cap and rotor timing is correct double check spark plug routes (mistakes happen). maybe your timing is off in general.

When it stove pipes, does the empty get caught by the next live round coming up on the carrier?

Try firing one round in the chamber and none in the mag and pump like normal.

If it fires and ejects the empty with no ammo in the mag the ejection system is probably fine.

If when you shoot with one in the chamber one in the magazine and it stove pipes you may have a timing problem. The cartridge stop is letting the next shell come into position and start coming up on the carrier to early. This may be fixed by moving the ramp on the action bar so as to get ejection farther along before the next shell is released to the carrier.

Caution, if the cartridge stops are ok and the carrier is coming up to early it is another issue altogether and needs to be looked at by a smith.

broiler igniter fires but lower burner igniter wont fire

It sounds lke you have water in the gas

remove /replace gas in tank