Keeping me up at night!!

SOURCE: 39cc McCulloch chain saw

I have the same exact saw as you and I was having the same troubles except I had to keep pumping the primer bulb to keep it running. I didn't want to go by a new saw because I knew I could fix it, as I am skilled in small engines, but have never actually taken a chainsaw apart. I dug into it and found that the fuel line that comes out of the side of the carburater and leads into the fuel tank with the fuel finlter on the end looked cracked a little. So i trimmed the end of it off and thought that it would work. It didn't! So I took it back apart (took the carb all the way out) and found that that fuel line was totally rotted underneath the carb and every time I pressed the primer bulb, fuel shot out of a large crack where the fuel line was bent. After I replaced that everything was running great. If you have any more problems, feel free to contact me. John

SOURCE: McCulloch 3200 takes many pulls to start, runs good when does.

I don't think I can help, but normal starting procedure for me is to put choke on, pull on recoil until it kicks over once. shut off choke and restart. Sounds like you have fixed almost everything & adjusted mag right. Rick

SOURCE: My McCulloch MS1838AV 38cc chainsaw has a broken

only way is to "mike" out the bearing areas and connecting rod journal. compare the original to the replacement. close is not good enough exact is what you want.

SOURCE: Need to remove & replace primer bulb on mcculloch mac 3516

There are 4 different IPLs for this saw. Fuel detail are on multiple illustrations.
http://www.ordertree.com/modelinfo/MCC/22-600035-18-Mac-3516-IPL-211318-01/139.22-600035-18-Mac-3516-IPL-211318-01.1.59.1.html
A helpful video, a few of my suggestions, and a schematic follow:
Fuel Line Replacement by SmallEng.com
http://www.youtube.com/watch?v=JrXpU70Hmi0

• The hose in the tank with the filter on the free end connects directly to the carburetor input connection.
• If the saw is equipped with a primer bulb, an output line from the carburetor connects to the suction side of the primer (once the bulb is collapsed it draws fuel from the tank through the carburetor to refill as it inflates).
• The pressure side of the primer returns displaced fuel to the tank as it is depressed.

SOURCE: Have a Mac 3214, fuel lines were rotten, replaced

The fuel metering needle in the lower carburetor chamber may have a bad rubber tip or the rubber diaphragm may be hard or cracked. McCullough fuel tanks vent through the cap (it should not have a gasket). Gravity plays no part in the carburetor fuel volume. Remove the spark plug (ignition off) and pull the engine through a few times without the choke on, but the throttle wide open to remove excess fuel in the crankcase (no smoking during this procedure). Make sure the plug is dry when you put it back. Hope this helps!