How to hold (fuel pump) gear to tighten nut?

I've come across this situation many times torquing gear retaining nuts on fuel pumps and hydraulic pumps when I didn't have the tool the manual calls for. An old man showed me when I was first starting out to just use a strap wrench around the gear teeth. Not one of those cheap rubber strap wrenches but a good a rigid brand one with a 12 or 18 inch handle, I'll post a link. To this day its the only thing I've ever used and it works every time. Best part is you don't have to worry about chipping gear teeth or slipping in a vice, just use it like a back up wrench.

Ridgid #5 Strap Wrench | Acme Tools

 

inside if vice, pug to big pieces of plywood on gear... the primer pump discussed here by qualitytruck and mhyn.

 

It will take little longer but it works. I have done it many times before.