Honda says that its power unit update for this weekend’s Canadian Grand Prix is focused on the internal combustion engine.

Mercedes, on the other hand, will hold off on updates due to the late manifestation of a ‘quality issue’.

Honda’s update for current partner Scuderia Toro Rosso is important not only for the immediate future, namely racing at the Circuit Gilles-Villeneuve, but also in Red Bull Racing’s deliberations regarding its engine supplier next year.

Red Bull’s senior operation’s team principal Christian Horner has pinpointed late-June to early-July as the time when it will make a decision as to whether to continue with Renault or also take on Honda power.

Honda Formula 1 technical director Toyoharu Tanabe said that an uplift in performance is the main aim of the update.

“We are introducing an updated PU for this event, fitting it to both cars,” Tanabe confirmed.

“The updates are mainly to the ICE, focusing on improving performance. The Montreal circuit is known for its long straights, where over 60 percent of the lap is spent at full throttle.

“There are slow corners after the long straights and this means that good driveability is again important as is rapid turbo response.

“All these features mean that the power unit is one of the key elements here, which is why it has traditionally been the venue for engine manufacturers to introduce updates.”

The new internal combustion engines are, however, the third for each of Pierre Gasly and Brendon Hartley for the season, meaning any subsequent engines would draw a grid penalty.

Hartley is also already up to his last allowable MGU-H, MGU-K, turbo, control electronics, and energy store.

Mercedes teams, meanwhile, will have to wait another round for their first power unit upgrades.

“Although we had hoped to introduce PU2 this weekend, a quality issue means that this has now been delayed by one race,” advised a Mercedes spokesperson.

“All Mercedes-powered cars will be running PU1 for this weekend, too, before receiving new units in France.”

The postponement affects the factory team as well as Force India and Williams.

Practice 1 for the Canadian Grand Prix starts at 0000 AEST on Saturday morning.