With an 85.4824 percentile in JEE Main and eligibility under the North East quota (EWS category), you have a decent chance of getting into SOE Tezpur's Mechanical or Civil Engineering branches, though it may depend on the specific round and seat availability.

Here’s what the recent cutoff trends suggest:

Mechanical Engineering:

2024 Closing Rank (General category, All India quota): Around 185140 for North East quota, the cutoff tends to be more relaxed, especially for reserved categories like EWS

Civil Engineering :

2024 Closing Rank (General category, All India quota): Around 209876 again, NE quota + EWS reservation could work in your favor

Since your percentile roughly translates to a rank near 140,000–160,000, you're within striking range, especially for Civil Engineering. Mechanical might be slightly tighter, but still possible depending on the round.
All The Best!

No, with 85.4824 percentile, you are unlikely to get Mechanical or Civil at SOE Tezpur through the North East quota under the EWS category.