Treasury Minister Alex Allinson says he's confident the Ben my Chree will be operating a normal service by TT.
The ferry, which is in Birkenhead for maintenance, is currently subject to a speed limit because of its emissions.
In Tynwald this week, Central Douglas MHK Chris Thomas asked whether the vessel would be back to full power in time for the motorsport festival.
Dr Allinson said the emissions calculations were based on inaccurate data, and he was confident the ferry would be operating as normal soon:
Motorsport event appealing for marshals
Rural road's poor condition closes it for weeks
50-mile Ultramarathon to launch in Island
Another yellow weather warning for coastal overtopping
Dental practice to relocate once more
Weather cancels two ferries today
Douglas Harbour bridge to temporarily close overnight
Weekly lunch club to combat loneliness
