carb cleaner

[kickinbull]

I have a Mac chainsaw that acts like the carb is messed up. I've taken it apart but saw nothing that would cause problems. It runs very good when first start up, then boggs and dies. Today it ran the longest so far, about 5 minutes. I have replaced all the fuel lines and filters and primer bulb. I was thinking that if I ran some kind of carb cleaner through it while running it may straighten out. The saw was given to me, and while using it today while it was running so good, I hate to just junk it.

 

[Kingfisher]

Full strength B12 carb clean. If its dirty that Chemtool brand is powerfull

 

[Kingfisher]

You sure a new line didn't come back off? I just redid one of those Macs and it was "tricky" but simple

 

[Nesikep]

How about the fuel tank vent? That's sounding like a good possibility. Sounds like it might be creating a vacuum in the fuel tank until it can't get anymore fuel. Try running it with the cap cracked open a bit.

Failing that, ignition wonky. If it is really running good for a while, in my experience the carb is usually good. Ignition coils often will work when cold and start to fail when warm, and spark plugs can do all sorts of weird stuff.

 

[wbvs58]

We are on the same page Nesi. The fuel tank air vent is the first thing I'd look at with the symptoms you describe.
Ken

 

[kickinbull]

Thanks for replys. I'll check the tank. I also was thinking it might be the coil. It's a discontinued item at most places. But it can be bought for around $65. Not wanting to go that far with it.

 

[mariareese]

I am too late to this When you head to the hills to cut wood for the end of the week, you must have to make sure and pack the proper chainsaw supplies or your workday might end rapidly. Learn from our 7 years of experience because it is very horrid to sit and wait for parts to arrive.

 

[Mat Man]

check vent in the gas cap.