I thank You Markus,I don't know much about the Tec ID and this engine is off of a old Snow Hound,(year unknown) and has a cover over the blower shroud and air cleaner to help with temps being cold,I replaced it with a blue H/F 6.5 after the plug hole stripped on the Tec. Can the year of the "HS 40" be I.D.ed by the numbers on the shroud? They are HS 40-55276E SER 50500 I will have to dig the H35 out of storage to get the numbers off of it,just a thought,instead of pitching it out just because of the bad plug threads!....