When applied to a 2 stroke engine, it describes an intermittent misfire caused by the mixture being rich. A rich mixture at idle helps with throttle response as small carburetors usually don't have an accelerator pump and the mixture can go too lean when accelerating. This condition is called "bog" . As in "My trimmer bogs out when I pull the trigger". Another term to describe the same thing is "gurgle" or "burbble".

While a plugged muffler or plugged exhaust ports will keep a LB from running right, it will not keep it from at least firing a few shots. Engine couldn't possibly have run to that point. Cleaning the muffler depends on WHAT muffler your LB has. The one pc. steel ones can be thrown in your charcoal grill when you have finished cooking and left. Tap/blow out when cooled. The muffler for the model number given is a 2 pc. cast aluminum one which easily comes apart for cleaning. Use some SeaFoam in your fuel for a few tanks full. Your trouble could be a lot of things. That model is the first one with CDI which continues to be a weak spot with LB. However, you say you have good spark so shouldn't be that. Could be bad crankcase seals or bad reed valves. Walt Conner

Since this Zama carb has NO primer bulb, I feel that old, swollen check valves in the MAIN NOZZLE and the IDLE circuit, may have been the contributing factor to the flooding; but Zama states it's flooding causes in regards to carbs with primer base assemblies on them. Even with lowered metering lever and new diaphragm and the mylar fuel pump (butyl rubber one pumps more)...flooding did occur. A test on the needle valve showed for the most part it was closing and opening properly (even though it was a USED needle valve). I probably should have got the RB kit, not the G & D kit. I will post one final time on this machine once the NEW carb is installed.

I got two of them at garage sale. First generation Mantis with the good Echo engines. Owner said they don't run and selling them for parts. Thats all it was dirty carb. One All I did was disassemble and clean it up used the old gaskets and diaphram It ran like a top afterwards which I done the exact same things as yugman suggested. The other one was really rusty inside the carb and took alot more cleaning and a new carb. kit. (cost me 8 bucks). But, the end result was the same, runs good now. I kept one and gave one to a co-worker These were mid 80's models and set for a very long time.