2020-05-28 Carb Swap
The carb clean didn't fix a thing. Somewhere there's a passage I'm not seeing to clear. At the carb end there's round press-fit stamped metal block off plate. I think it's behind that plate. To remove the plate would be foolish..So I bought an Amazon from China carb for 40 USD. It came with air filter, spark plug, carb, and gasket.
Machining on the new carb is a bit rough, but good enough.
First some pics of the linkage, since I forgot I had already taken pictures earlier.... sigh.
Throttle cable.
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The block off plate talked about above seen in this pic.
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New carb. Didn't fit. The feedback link interferes with the choke cam.
Ended up swapping this carb for a used carb off a 3.5 hp Briggs and Stratton. Rototiller has a 4 hp Briggs. The only difference is the fuel pick up length. The 3.5 hp has a smaller gas tank, thus a shorter pickup tube. So when installed in a larger, deeper tank, it won't pick up all the fuel.
But it now runs great, so for now I'm done. Later, I'll get a longer pick up tube. Looks like the part is available separately.