I never installed a fuel pressure gauge but it looks easy enough. 2 small bolts, a small rubber hose, and another thing on the gauge that evidentially has a small rubber ‘o’ ring gasket like thing on the end of a nipple on the gauge, and presses against a metal tube when installed.

As I said, looks simple enough but here’s the question-that rubber gasket ‘o’ ring thing that presses and seals against the small tube-should that rubber ring be dabbed with a bit of grease or something else to help make the seal tight?

Thanks.