Yes, definitely can count revs. Cranking is slow. I'll check with
the parts store and see if they have a starter motor tester. I have a
repair manual with spec for the starter motor.
I found that I can remove the starter motor quite easily without
messing with the flywheel. It is puzzling to me that the manual
suggests removing the flywheel to get to the starter. Doing so might
make removal marginally easier, but getting that flywheel off looks
like a big project unless you just the right tools.
I take it at this point everyone agrees that I need to remove the
head? I'll probably do that on Sunday unless someone can suggest
additional testing before doing so.
Ether Jones wrote:
PaulD wrote:

Ether or anyone else who can answer: Do you think the possible
valve problem is causing the cranking problem? Or do I still maybe
need a new starter?

It's difficult to say without quantitative information. Can you
quantify how fast the engine is cranking? Put a piece of masking tape
on the rotating screen. Is it slow enough that you can count the revs
while somebody else keeps time?

Or, how difficult is it to pull the starter? Your local parts store
that charges batteries for free sounds helpful. Do they have a test
stand for testing small engine starter motors?