I noticed one crew list record that could be your John Teare before he emigrated:-

Name: John Teare
Age: 24
Birth Place: Isle of Man
Capacity: AB
Voyage commenced: Liverpool 24 Jun 1873
Termination of voyage: Liverpool 10 Jul 1874
Port of Registry: Liverpool, Lancashire, England
Ship Name: Hertfordshire
Official Number: 47595

This John Teare completed this long voyage but the records show that on this voyage and previous voyages there were desertions from the crew at San Francisco and in South America.