Eraser - I fought with my 3W 100 for most of the past 6 months. I fly almost weekly and some days I'd have good experience, and some days i'd get random quitting of the engine. I chased the needle valves all over the place. Most experts say that when the engine quits during transition from idle to full, the idle NV is set too lean. Or that when it quits at full throttle it may be too lean, etc. All of this is probably true, but I found another cause. My ignition had intermittent failure. Finally, it got to the point that it would only run on one cylinder. This was obvious as the engine had no power and one cylinder was cold even after running a few minutes. I swapped the spark plug leads and moved the problem from one cylinder to the other. So definietly it is the ignition. So I buy another ignition and all of my problems are solved. The engine runs as good as new. I'm pretty sure the ignition was causing most of my problems over the past 6 months. Thankfully it finally quit in a way that forced me to buy another one. I have a dozen or more flights since replacing the ignition and it has never quit since. If you can afford to buy another ignition, I'd try this before buying another carb. Or if you can borrow someones ignition, try that approach.

By the way, I've had 4 ignitions in 5 years. the first two quit in a way that was easily diagnosed -- a hard failure. The third one is the one that messed me up for 6 months. The fourth one has been running for a few weeks now with no problem. The first 2 ignitions were from 3w. the next two I got from DA. (the DA and 3W ignitions are interchangeable). I understand that C&H has an ignition for the 3W now also.