If I have a Gear Svellsongur attached to the Ornn, I will have Deflect 4, but if someone targets with a spell my Gear, do they have to pay Deflect 2?

No, they do not have to pay any Deflect when targeting Svellsongur directly.

When a spell targets the gear (Svellsongur) rather than the unit (Ornn), Deflect doesn't apply. Here's why:

1. Deflect is on the unit, not the gear. Ornn has Deflect 4, but that protection belongs to him. Svellsongur is a separate game object — targeting the gear is not the same as targeting Ornn (FAQ #734, #9176).

2. The gear's own printed rules text is inactive while attached (Rules 718.2, 135.4). Even if Svellsongur somehow had Deflect printed on it, that text would be inactive while attached. And its effect text (the copying ability) grants Deflect to the unit, not to the equipment card itself (FAQ #7465).

So: targeting your Svellsongur with something like Salvage or Detonate costs zero extra Power. Only spells or abilities that choose Ornn himself have to pay the Deflect 4.