Basically, here is the answer that I discovered for mine:
“Short stem on primer bulb, has short fuel line to the carburetor. Long stem on primer bulb, has long fuel line to the fuel tank.
Video:
I recently bought a 38cc Chainsaw on Craigslist for $30. However, once I showed up at the garage sale location, the lady replied “Oh…by the way…my husband always had difficulty getting it to start and run properly”…NOW SHE TELLS ME… (that is when I took the opportunity to offer her $30 instead of the $50 she was asking

).
After I got back home, I tried using the primer bulb…but no fuel would flow into it (Plugged? Fuel Lines on Backwards? Fuel Lines Disconnected?)
Next, I primed it with gas down the spark plug hole and it started right up and would Idle properly, however; I discovered that it would stall each time when I tried revving up the engine. Time for a YouTube search …See link above
Finally, I needed to take peek under the hood! I removed the cover (incidentally, there was barely any sawdust in the crooks & crannies…chainsaw looked like it was practically brand new!) and popped off one of the fuel lines from the bulb to confirm they were on the right way…(they were).
—-> It was when I removed one of the the fuel lines from primer bulb that I heard a “vacuum release hissing sound”….hmmm, imagine that?
So, I plugged it right back into the primer bulb and reinstalled the cover, then I pumped the bulb a couple times and FIRED IT RIGHT UP…REVVED UP WITHOUT ISSUE! RUNS AWESOME
Conclusion: Due to the fact that the Lady said that her husband had problems with it from the very beginning, my guess is that the fuel line was kinked from the factory…which caused a vapor-lock when the bulb was pressed…and the rest is history.
End result: Not a bad deal…practically brand new 38cc Craftsman Chainsaw for $30
