I just realized that the muffler (the box said Webra) that I bought for my Webra Blackhead, which originally had an exhaust plate, does not have a nipple for the fuel tank breather line.

What purpose does that line serve and what can I do??

Thank you in advance

harphunt, you connect the vent line to the muffler to pressurize the tank. That gives you a more even run from full to empty tank. w/o pressure, you end up running too rich @ the beginning, to keep from going too lean @ the end of the flight. Some engines won't run w/o pressure, or they'll run un-reliably. You can get pressure fittings @ a hobby shop, or @ an on-line dealer...You just gotta tap the muffler for the fitting.

Thanks for the info! I found a tapped hole in an inconspicous place, so the problem is solved and my question answered.

Thanks