Take the two round silver inspection covers off that bottom cover and do it again, look at what is going on downstairs. Hopefully you don't see the starter clutch moving. Then take the top small cover off, hold the pin for the idler gear with your thumb (better with the spark plugs out) and tap the starter button lightly to see whats up. Last thing is to take the idler gear out, and hit the starter button again to see how and if that starter is turning. Your set pin holes looked a little hammered, but that just may be that nasty sealant somebody used. Find the problem, fix it, clean the gasket surfaces and put a few gaskets in, less than $20 .
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