OK, so I got the B/S (Craftsman) 29cc running. BTY a star type lock washer works fine to lock the prop hub to the flywheel. IT turns up 5K RPM with a 20x10 and that is enough power for what I want. That is, when I hold my finger just so to partially choke it. I took the carb apart and the flexible compontents flex. There is no obvious junk in the jets. The pop valve does it's teeter totter thing. I swapped the in and out lines just in case.

http://wem.walbro.com/walbro/product...=WYL%2D229%2D1

This carb has no ajustments for fuel flow. On general priciple that bothers me.

What am I missing? Does this type of carb need a restriction on the inlet to work? Should I throw this carb away and put a real WT carb on it with the crank case vent line acting on the pressure tap to operate the diaphram? Make a pressure tap on the inlet manifold venturi?

So what is the scoop on 4- stroke carbs?

Hmmm, look up the info on the Honda engines here on the web. But the bottom line is, whether you stay with the rotary type carb or not, you need to have mixture adjustment available.

When an engine is run with more free breathing exhaust, OR intake, (like no air filter), it is going to lean out. Without being able to adjust the carb mixture, you are out of luck.

I think some guys have successfully drilled out the main jet, but the right fix is an adjustable carb. If your engine has the WYK series carb on it, they sell that model with mixture adjustments. Sorry, I don't know the applicable carb numbers. I successfully converted my Honda from a WYK type carb to a WT, but I would recommend staying with the WYK style carb.

AV8TOR

The WYD seems to be the only rotary one with H & L needles? They are used on the Saito 30 & 36cc four strokes

Or you could go with a WT456-1 from a Ryobi 31cc four stroke

I would use a WYK 16-1 Works great on a Hond GX31. It has dual needles, no primer bulb, and will run off of intake manifold pulse. I have found if you are carefull, a new notch can be made with a Dremel to unload the return spring tension on rotary Walbro carbs . Don't screw up the mating surface.
Most of the other Walbro rotary carbs have a idle adjustment in the center of the bellcrank on top. You may have to carefully dig out a potting material to get to it or pop off a plastic plug. If you also drill out the main jet carefully they work ok.
motorhd

The Low Speed needle on the WYD is in the center of the throttle arm. It works much like a glow engine carb except the barrel spring holds the barrel in instead of out.

On these, you can close the throttle and pull out on the barrel to choke the engine

I made a thick washer that goes between the carb and the intake. The washer has piece of brass tubing stuck in it , like a lolly pop. That tube connects to a port that operate the carb's pump. In put a Tee in the crankcase vent and connected it to the washer, presto, the pump works. With a Zama of about 9mm the engine runs. It will fun fast, it will run slow. It will not run fast and slow with the same settings or transisiton worth a darn. I played with the original carb. I smoked my starter. Enough of this one. Maybe if I can find a "Four-mix" or a Honda I'll revisit 4- strokes. For now I'll stick with what works.