good luck
had too many miles in the ditch with no wind too much tide
and too much oil smoke at 1 to 10
but they do not die just get hard to start and smoke more
propane torch is a major seagull tool
both to unFOUL the plug and a quick start aid
hot plug trick remember 1 to 10 the plug is always foul
and to heat bend the drive spring to reuse a busted one
if it ain't witworth or odd sized it likely will break if looked at hard
real advice sell it as a wall mount decoration
and skip the COPD from the oil
and buy a jap 4 stroke
still have one like that but no sparks and short shaft
if a person needs a seagull they best have 2
as far as I know they died years ago
parts are few and high priced now
https://www.britishseagull.com/spareparts.php