McCulloch 10-10 fuel issues

[SASKJ03]

Hello just recently bought a house and decided to drag my old mcculloch 10-10 out of storage to do some cleanup around the house. Had to rebuild the carb and also swapped the chain break with another I had so I could install the spikes. Saw will run great all day and cut no problem but once I turn it off and come back to it the next day there is always fuel pooled into the air box. Saw will fire up again with just a few pulls. Not sure where the fuel is coming from at this point it’s driving me nuts. I don’t believe it’s the tank seal but do have one ordered to try.

 

[heimannm]

If it has been setting empty, the cork fuel tank gasket may have shrunk a bit. Sometime leaving them with fuel will allow the gasket to swell and seal again, but not always.

It is also possible that the fuel line is leaking where it passes through the tank. Check the fuel line to see if it is loose, and if it is suspect pull the line out (into the fuel tank) and put a few wraps of Teflon thread tape around the line and reinstall it.

Mark

 

[SASKJ03]

If it has been setting empty, the cork fuel tank gasket may have shrunk a bit. Sometime leaving them with fuel will allow the gasket to swell and seal again, but not always.

It is also possible that the fuel line is leaking where it passes through the tank. Check the fuel line to see if it is loose, and if it is suspect pull the line out (into the fuel tank) and put a few wraps of Teflon thread tape around the line and reinstall it.

Mark

Finally got the new tank seal in the mail and got it installed. Filled tank to the top and let it sit unused for several days and air box remained dry. Used it this past weekend and Monday morning the air box was full of fuel again. At this point I’m thinking the needle and seat are not closing all the way when saw is shut off. It can’t be the pass through for fuel line as it was dry when it sat unused. I’ll take the carb back apart next and inspect again.

 

[heimannm]

If the needle is leaking that much your saw will be flooded when you try to start it after setting. Pressure test the carburetor and make sure the needle is seating properly and that the gaskets to the carburetor body (metering and fuel pump side) are not leaking.

Mark

 

[MacAttack]

I wonder if fuel could be leaking past the Hi / Lo adjustment needles. I can't recall on a 10-10 if they're sealed with O-rings.
Either that or the fuel pump gasket, would be my guess.

 

[Rallyeguy]

Finally got the new tank seal in the mail and got it installed. Filled tank to the top and let it sit unused for several days and air box remained dry. Used it this past weekend and Monday morning the air box was full of fuel again. At this point I’m thinking the needle and seat are not closing all the way when saw is shut off. It can’t be the pass through for fuel line as it was dry when it sat unused. I’ll take the carb back apart next and inspect again.

Just checking on if you did anything with the fuel line like Mark suggested. This is a very common leak area and I wouldn't rule this out as being the culprit.