Nebraska Cowman once sent me a link for this free IH magneto online repair manual...
Google "GSS-5035 Service Manual Magnetos" and click on the top link of the list Google generates.
When that manual webpage opens - click on PAGE 39 for H4 info. Also has info on many other IH magnetos.
Did not post the actual link, because I did one time and it either would not work or was removed or something.