HP 2.5 Tiller Arm Thread Size?

[Propster]

I have an early 90's 245 hp 2.5 carb motor and the threads on the tiller arm need to be cleaned up (little surface rust) (2 bolt mount). The holes look to be 5/16 fine thread, but I don't want to clean them with the wrong size tap.

Any one know?

[mn808gade]

i think ALL tiller arm bolts are the same 3/8 fine

[tux974]

5/16" fine is correct!
The 4 holes on the swivel section are 1/4" fine.
I usually put the taps on a drill and run them with a bit of oil.

[Propster]

Thanks guys. Yep, 5/16 X 24 (fine). Cleaned up nice.