Stihl012 puking gas

[basspapaw]

I rebuilt the carb replaced fuel line and tank vent and it is still puking gas with not very much power Im not sure about the reeds could they be my problem?

[Texas-Jim]

I'm not at the shop so im not 100% sure but i dont think the 012 has reeds.
But in either case id check compression first. A broken or worn ring can allow pressure to bleed past and out carb and loss of power as well. All or most all 2 strokes will spit a fine mist but its very  tiny amount. not enough to saturate the filter.

[joe_indi]

If your metering level is not set correctly or if the metering needle is worn, this could happen.
I have also seen this happen when the ignition timing was off (retarded) from a damaged woodruff key).
Post script: It has no reed valve, but the parts diagram does show a 'Diaphragm' between the carb and engine block. 

Joe

[basspapaw]

Thanks I did a compression test and it was a little low then i went ahead and took the diaphragm from below the carb off and it sure looks like a reed valve to me it had a broken shim like piece of metal fall out when I took it off, I looked and they call it a inlet reed valve, I ordered one for it. could this cause low compression?   

[stihlsolo]

That thin metal piece was the actual reed, the thicker piece is the reed stop. Since the 012 is case-port, the reed valve prevents blowback through the carb. Broken, the reed won't close and you have a open crankcase that can blow back through the port manifold and carb. With a broken reed, you get the puking (blowback) you had, and if the rings allow leakage back into the crankcase, maybe low compression.

Check to see if the reed broke cleanly without little pieces breaking off. Luckily the combination of the reed stop and crankcase opening size, shape and taper should have kept a whole broken reed or large piece from dropping into the crankcase.

I like the 012 (have 2): 45cc's in a small light package.

[basspapaw]

Thanks  it looks like it broke clean across ,Ive ordered a new one and hope to have it in the next day or so and will keep you posted

[Fifelaker]

A broken reed will not cause low compression. What is "a little low"? I am not sure what is considered low on that model, but if it were mine I would pull the muffler and take a look at the piston , rings and cylinder. If the piston and cylinder look good (no scratches or transfer) I would consider rings, if the compression is indeed low. Does your gauge have a Schrader valve at the end of the hose and did you pull the string until it quit climbing?

[basspapaw]

Update I replaced reed valve and gaskets . The saw starts and runs like a new one! The compression is about 140 cold,my gauge is a cheap one from ebay so it might not be reading correct,  Thanks for all the help