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That engine is a thing of beauty, by far the prettiest rebuild of a Kirby-Lauson I've seen. Your pictures and explanations are excellent - I think this will be a very useful thread in the archives.
Five comments on your explanations.
First, I think 1,700 rpm is the Lauson's idle speed, not its maximum, which is probably about 3,000 or so. The fixed ignition timing is a shortcoming these engines share with Briggs side valve engines: it is set so that the engine will not kick back during starting, and is then hopelessly retarded for maximum power. Honda avoided the problem by using a truly massive cast iron flywheel together with a decompressor, then were able to use a static timing of 26 degrees BTDC on their OHV engines, compared with just 6 degrees for Briggs side valve engines. In reality low compression side valve engines have slow burn rates and actually need even more advance than the Honda OHV has. Briggs decided, quite sensibly, that making the engine light and cheap was way more important than making it powerful, because people who want more power can simply buy a larger engine. (Also, the SAE power test procedure all the manufacturers use allows them to optimise the ignition timing during the dynamometer test, even though production engines then have much lower power output than they advertise, because they have a fixed advance of only a few degrees.)
Second, your governor spring has had the final gong and should be dragged off-stage by the proverbial shepherd's crook. It is supposed to be a close-coiled spring, and once stretched, cannot be recovered to a state where it will have the correct characteristics.
Third, the high and low speed screws restrict the movement of the governor arm to set the maximum and minimum governed speeds. The minimum is probably not important since the idle speed is set by the idle speed screw on the carburetor throttle butterfly valve, though setting it on the governor as well probably helps keep the transition smooth. The high speed setting is important because it controls the maximum speed the governor will allow the engine to reach. After all your good work, it would be a pity if the engine tried for 5,000 rpm and fouled its britches in the process.
Fourth, I looked up the Lauson engine specifications here:
http://lausonsmallengines.com/literature/specifications/tecumseh/H.PDFThat states that the H30A has a pneumatic governor. The Kirby Lauson has a mechanical governor.
Fifth, a very fine point of procedure, usually of no importance: anti-friction bearings, whether ball or roller, are conventionally installed with the type number facing outward, so people can see the type without removing it. (Tapered roller or angular contact ball bearings have to be installed to carry the thrust in the required direction, of course, regardless of type number locations.) For a jolly and entertaining read of myriad trivia of this ilk, see the Honda Common Service Manual, all 393 pages of it, available as a free download from here:
http://www.vf750fd.com/vf750f/Honda_Common_Service_Manual.pdfIf you would rather not have these comments in your thread, just PM me and we can find a solution. Because you wrote such an excellent thread, I've applied an extremely tough standard of "marking".
