RE: Four Stroke Glow To Gas
Compression is not a problem, you will have controlled spark timing so you can control detonation. The longer taper and the finer threads
are to make the needle less sensitive. Most twin needle glow carbs can be set lean enough at idle and full throttle, but the groove in the throttle is a straight line. So you need to make a barrel with a curved groove in it so that barrel turns it does not open the main fuel inlet as far in the middle and this will make it lean enough. Both the high and low would be stock placemnt on the groove. Its a matter of cut and paste. Last one I did took about 7 tries to get it right.
Have the crank pin checked for hardness, its needs to be 60 rockwell to run needles on, most pins for bushed engines are in the 30 range