I need to replace the oil line on my Mac 3214 chainsaw. Any idea where I can get the part

SOURCE: need to replace gas line inside mcculloch chain

You need to disassemble the case to get to the fuel tank. Pull out the plug fitting and replace the internals with new factory grade parts.

SOURCE: I have a Mac 3214 chain saw and I do not have the mix ratio

40 to 1 is the ratio

SOURCE: Gas Oil Mixture

Fuel Mix: Add 6 oz. McCulloch custom lubricant or 1 PT. S.A.E. 40 (16:1) to 2 U.S. Gal. Regular Gas

SOURCE: I have a McCulloch Mac 3214 32cc chain saw. I can

40 to 1

SOURCE: where can i get a diagram to show me how to

Afternoon Jimmy;
Let us begin with the IPL. The IPL (exploded parts list) for your saw is the only detail for fuel line routing and it is sketchy at best. Fuel components and part numbers are listed but may be on different illustrations. They are also beneficial with disassembly/reassembly:
McCulloch MTD (7 - 3214s to choose from)
Chainsaws 32cc-35cc
Use page 1 above to find a more detailed IPL here:
McCulloch IPLs
http://www.ordertree.com/modelinfo/McCulloch/139.59.html
21 prefix example "600032" for a 07 suffix follows:
http://www.ordertree.com/modelinfo/MCC/21-600032-07-Mac-3214-IPL-211229-01/139.21-600032-07-Mac-3214-IPL-211229-01.1.59.1.html

The IPL in conjunction with this should provide ample guidance.
http://www.fixya.com/support/r3706813-2_cycle_fuel_system_repair

If you have more questions or need additional help please reply below and I will get back to you. Thank you for using FixYa and Good Luck. HTH
Lou