Received the following response from Tohatsu concerning breaking shear pins.
Info may help, especially the stainless steel shear pin reference.
Bob,
Yes the idle speed can cause the shear pin to break when shifting from forward
to neutral, also if the 3.5 is pushing a heavy boat this can cause the
breaking of the shear pin. If changing the idle does not help you may want to
go to a stainless steel pin, our part number 30964-1260M. Yes the small screw
you are talking about is the idle adjustment screw. (left side of cowling)
If I can be of any further assistance please let me know.
Kurt Gardner
Tohatsu Outboards
Bob Kalisz
P-19, #844
Frankfort, Ky.