Honda Hondex HE-773-III-Di Operation Manual page 78

6. Use and fix it with Pipe(tank) guide (B) when pipe length is 410mm or more.
M5 nut
Angled guide
No need to use pipe(tank) guide (B) if pipe length is less than 410mm.
Round guide:
Screw side
Pipe guide(B)
Fix it to pipe guide (A) with M5
screw.
73
M5×20 Pan head screw
M5 Spring washer