[xb-60]

Thanks for the advice so far.
New tank, so it's OK Gary, no residual fuel/vapors.
I'll use grease as suggested. The main hole dia. only needs to be around 32mm min. so will be hard to use a vacuum cleaner.
I'll rinse it out with thinners.
I'm assuming that I should use a thread locker on the attaching screws, as the flange of the unit will be about 40mm lower (in a recessed 'cup') than the top of the tank.
Is loctite threadlocker fuel proof? If not, what is?

Cheers,
Glen