Thanks for the parts diagram but I am nor sure if it helps with my current problem. The problem remains where the other pipe from the fuel tank should go. It is definitely not to the carb with my saw. IT seemed to be coming from a gap in the casing that led to the lower side of the engine. There is a brass ferrel in the pipe and I have convinced myself that it is some sort of system that uses pressure from the crankcase to pressurize the fuel tank but I am not sure where I got that from! Fact is despite pressure washing the engine, I just cannot see where the pipe should go. Any suggestions would be gratefully appreciated.

What have you done related to finding the problem? Such as: 1. Disasemling, inspecting and cleaning the carb for restrictions all ports/screen, bad diaphragm and etc. 2. Replacing all fuel lines, primer bulb, fuel filter and clean fuel tank if needed. 3.You should see some fuel in the bulb and see it moving while pumping or that's restriction IMO. Good Luck!

Hey Centerline... Yeah, old Macs are tough to find parts for. I run (just for fun, and only occasionally cuz it's so loud!) an old 710 Auto...it's pure testosterone. But onto your problem....make sure your bar nut tightening technique is correct: you are lifting up on the bar nose while tightening, right? (This puts the bar/chain in it's "cutting" orientation. You'll notice that if you let the bar hang down prior to tightening the bar nuts, the chain will be looser; when you cut -- assuming you're cutting with the bottom of the bar -- you force the bar up, tightening the chain.) Unless the sprocket is terribly gutted, chain climb should not be the problem. As you say, it's oiling, so excessive heat shouldn't be the problem. How is the tensioning screw assembly? Does it fit properly in the bar tensioning hole? Is there a lot of slop there? Often times I see people torquing the bar nuts to 5 million foot-pounds trying the keep the bar from moving and ignoring the real problem. It usually doesn't work, and tends to make things worse. If you're the type, keep an eye in eBay for the saw; if it's there you can occasionally pick up a carcass for parts for very cheap. It's not there now, I looked... Anyway, call Baileys at (800) 322 4539 and ask them about parts. They probably won't have them, but they should be able to refer you to someone who does, Oh, Baileys is a big logging outfit in California...nice folks, cheap prices, knowledgeable. Website at baileys-online.com. (I don't work for them!) Cut safe! Fid

presurizing the tank usually does nothing if the grit that clogged the oil passages is hard, you will probably have to use carb. cleaner and cleaning brush or wire to unblock? Does it have manual or automatic oiler? oil exit to chain should be no different. Should have oil slots, holes miled into the bar that aligns with slots holes in the saw side plate between the studs that holds the bar on for adjustments. I would try to google manual for your model see what you got.