I laughed, but I also checked to make sure it wasn't running backwards

First thing I'll try tomorrow is the other flywheel. Swapping out the coil is a pain - you have to remove the carb box...and these lil things are all fiddly. That will happen second if the flywheel doesn't work. Once thing I did notice was the flywheel that was on the Makita was a bit lighter than the one off the Dolmar.
Some things to note:
The tubing wasn't very tight fitting. The hose from the tank to the bubble came loose(but it still ran!).
The carb boot is a press on fit. No hose band clamp/jubilee clip retainer(jubilee is a brand in the UK). I had to install the carb twice because I am retarded - so, when I installed the boot, I shoved a pinky down it's throat to make sure it was a solid fit to the cylinder since you can't really tell if it's flush from the outside. The tightness doesn't inspire confidence. But it seems to work fine.
4300 came with a small spark plug, old 420 had a 'standard' plug
Flywheel is a bit wide for this size saw. But I think my 241 flywheel may be even bigger. I'll measure them when I pick up my 241 from the estate.
When I find time to cut on the estate, I'll try to have it next to the heavily ported ms241(that started detonating last time I used it hard), and maybe an Echo 390ESX and an Echo 360WES.
188psi compression and a 17" 325 B&C: