Does spark jump jump a gap of 3/8" on a test device , yes or no ?-----It will help just you to answer this simple question !----Is the thermostat installed and working properly ?
The pump operates with PRESSURE pulses not vacuum.-----And there is fuel in the crankcase so you might see some moisture there.-----Does spark jump a gap of 3/8" on both leads ?-----Does your primer PUMP on the hose go hard ?
Does spark jump a gap of 3/8" ( 1 cm ) on both leads ?----Yes a leaking diaphragm is common.----New diaphragm are easy to get / make .----Easy to install.
You put some hot water on the pistons.-----The piston heat up .----The ring groove gets a wee bit wider.-----Then with tapping the rings they may come loose.----Some might argue , I have done this many times with success.----Noted the condition of the pistons.-----I think those pistons and rings...
You likely need 4 new O/S pistons and rings.------No point putting new rings on old pistons.------With a manual and some wrenching ability you can do this.-----Start by pulling that head off for inspection.-----I like pictures.-----Maybe it just needs new head gasket.
I would some wee coils many years ago.---Eddy current probes they were.------Magnet wire was 003" diameter.-----So the bigger wire for a stator coil would not be hard to do.------Count the number of turns as you take it off.
Use boiling water on the piston.-----Use plastic end of screwdriver to ---tap, tap ,tap on the rings.-----That often gets them loose.-----Use broken end of rings to clean grooves.-----Boiling water also makes it easier to remove / install wrist pins.
Reverse does not do a lot of work.----It is almost always fine.-----Remove nut on bottom of driveshaft and remove driveshaft.----Then push shift rod all the way down and remove it.----Then pull out propshaft.
