I have a 750 with a B&S 7HP (170401) which leaks oil. Initially it had been leaking from around the breather assembly; which the PO removed for access, but didn't put a new gasket in. I fixed that only to discover that there's another leak, which appears to be near the oil filler tube/plug, so I'm guessing the crankcase gasket is leaking.
I have close to zero experience with small engines, but I can read, visualize the problem, and typically can follow directions so I think this should be within my ability to do and thus a chance to learn. By reading the "Illustrated Parts List for Model Series 170400 to 170466" I think I've found the parts I need, the oil seal (29843) and the crankcase gasket, of which there are several thicknesses. What thickness gasket do I need, the list a 0.005, 1/16", and 0.009?
While I have it open, is there any other maintenance I should be doing or other parts I should be replacing? The engine otherwise appears to run well and starts easily.
I have a few other parts I am looking for as well, such as the drive bearing (1800418) as well, so comments from vendors or members with spares would be appreciated.
Lastly, the engine runs louder than I would prefer and keeping it stock isn't a huge concern as a PO has made a number of other modifications. Is there a different muffler or stack which can be added to reduce the noise levels?