Zack is finally found before the final stage of the game, within the annex (storage building) at the far left of the island. You will need to recover the two missing parts to finish building his Mech walker, then enter and defeat the monster plants within the annex.
There are no windows that open inward on Steamworks Island. There is a skylight in the City Hall that can be opened with the Multi-Tool. You go out the hatch above Zack's room in the living quarters, to reach the Mech Crank on the vines.
you throw your computer because it frustrstes you so much...
its in the museum on mainstreet of steamworks island :)
It's Steamworks Island #14th Island
(The solution is at the related question "How do you beat Steamworks Island")
the crab on steamworks island is next to the living quarters
You go to Steamworks and head to the museum and there is the Deogen
The unfinished Mech that Zack was working on is in the garage next to Sully's. You need the Mech Motor and Mech Crank to finish it.In the garage next to sully's shop on the left side of the island.
steamworks island
Zack is finally found before the final stage of the game, within the annex (storage building) at the far left of the island. You will need to recover the two missing parts to finish building his Mech walker, then enter and defeat the monster plants within the annex.
There is a video walkthrough at the related link below. There are written WikiAnswers solutions at the related questions, as there are for all Poptropica islands. (How do you beat Steamworks Island) (What is the walkthrough for Steamworks Island)
Steamworks island