Mercedes delayed the use of the new engine due to a "quality problem" that occurred in the last minute before the Canadian Grand Prix.
The German carmaker plans to make this year's second power unit at the Canadian Grand Prix this weekend, along with the factory team, as well as two customer teams -Force India and Williams.
The transition to the new power unit would be crucial for teams using the Mercedes engine at the Gilles Villeneuve circuit, where power was on the forefront.
However, Mercedes has decided not to pass the new power unit in Montreal with a decision late Wednesday after the worries of durability.
The team spokesman said, "Even if we do not go to the second power unit this weekend, this quality problem we are experiencing causes a race delay in updating."
"All vehicles using the Mercedes engine will be using the first power unit this weekend before moving on to a new unit in France." said.
While the German team's champion Ferrari is expected to pass on a new version of the engine in Montreal, Renault continues to keep an eye on its plans and seems likely to switch to a new power unit this week with Red Bull.