Hard starting H

Although the carb or other thigns can cause your symptoms, I suspect a weak magneto spring may be the problem, because when its pull started or above 250 RPM or so, the spring and trip are out of the equation. With the plugs removed and wires attached but them up against the frame and you crank her over, does the mag produce a loud sharp SNAP and the plugs produce a good blue, as opposed to a thin faint yellow spark???? If they do, then I no longer suspect this problem and go on to the carb settings etc like clooney and others mentioned. If she kicks back when hand craning, retard the mags start timing a bit (rotate CW) but if shes snapping over and firing to late after TDC, advance it (CCW).

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God Bless the USA Ol John T Nordhoff

~That might be a rather hard problem to figure out & will take trying different things to eliminate them one by one.

~Start with the obvious; Does the mag snap when the flywheel is turned over real slow?--- [if not that's your problem].

~If the mag snaps, take an old [known good] spark plug & open the gap to 3/16" [use a 3/16" drill bit as a gap gage]. Install that plug in one plug wire at a time & lay on the block, then crank the engine by hand [you need a blue spark that jumps that 3/16 gap multiple times in a row, not just once].

~If all OK so far, try different choke settings [in some cases too much choke won't let any air in with the fuel & it won't get to the cylinders]. Just as a "see what happens" try cranking with full choke 1st turn, 7/8 choke 2nd turn, 3/4 choke 3rd turn, 1/2 choke 4th turn. If no fire go back to 3/4 choke for a turn or 2, then no choke & wide open throttle for the next few.

~Try different throttle settings, my H likes as little throttle as possible & still run after starting [just slightly off the carb throttle lever stop pin].

~Make sure the carb choke plate is closing ALL the way & not bent. Make sure the choke plate trap door is there, the spring is functional, & the trap door is opening towards the carb.

~Try opening the carb load & idle needles 1-2 more turns each [just for starting].

~Make sure you have the correct solid metal center plug wires [not automobile TVRS carbon resistor wires]

~Try opening the spark plug gap to .035" [that helps on my personal H]

~Give it a cold hand cranking compression test, leave one spark plug in & test the hand cranking compression on the other, then do the other side. See what the compression is with the choke on & only after one time over with the flywheel [starting compression].

~If you already haven't done so, install NEW gasoline [regular, no premium] & with no alcohol content if possible.

~Make sure the throttle plate is centered in the cab bore & isn't worn on the ends [that is a big factor in low RPM cranking starting].

~When you stop the engine, shut the fuel off & run the carb dry, or open the carb drain valve after shut down.

~If you have exhausted all of the above [& yourself] it's time to try substituting a different mag, & trying a different carb