Could earlier American entry rescue Russia?

Would the United States entering the First World War earlier save Imperial Russia?

No by itself; American aid would take time to mobilize and still need a practical route into Russia.

The amount of aid available and the transport route needed to deliver it are separate problems. Even if the United States entered in 1914, it would still require a long mobilization before contributing at full strength. More American production cannot stabilize Russian armies if ports, railways, and sea access remain inadequate. The most useful American contribution would therefore depend on the same Dardanelles solution rather than replacing it. Logistics sets the ceiling on coalition power in this case.