Ralph, is that accelerator pump on every Walbro carb? I've detached the spring on several of them, but didn't notice any problem. Then again, I could've had a problem and just not know it.

As for reducing the fins, I agree it's more a cosmetic thing more than anything. I did that on a Ryobi 31cc way back when. Thinned every one of the fins and shave off the front and corners, all by hand. Ended up saving less than 1 Oz. Hardly worth all the work I spent on it. If you have machine tools that can do this efficiently, that might be a different story. Otherwise, cutting the fins is only worth doing if it will help the engine fit in the aircraft better.

Still, if you are willing to spend the time, and cut the fins as part of an grand scheme to reduce weight, then the overall result might just be worthwhile. For example:

1. Cutting off the rear shaft on some engines
2. Shaving off unecessary webbing, appendages and bosses
3. Fluting and/or coring the prop hub, flywheel, and other rotating parts.

An Oz here, an Oz there, might add up to a significant amount.