Mercedes has confirmed that a power-unit-related technical problem caused George Russell’s engine revs to rise uncontrollably before the start of the 2026 Hungarian Grand Prix, ultimately triggering anti-stall and costing him several positions. Although George Russell attempted to control the situation through the throttle, Toto Wolff explained that the driver’s actions were a response to the fault rather than its cause.
Hungary brought George Russell more frustration after a difficult opening half of the season. A fluid leak caused by running over a kerb had already damaged his engine on Saturday, forcing Mercedes to fit a replacement power unit before the race. At the start, the British driver was then left almost stationary on the grid when his W17 entered anti-stall.
George Russell’s difficult Hungarian GP weekend
George Russell’s weekend in Budapest reflected many of the missed opportunities that have shaped his season. It was not necessarily a case of Mercedes wasting the potential to fight at the very front, as George Russell acknowledged that even without Saturday’s problem, a top-three qualifying result would have been difficult.
Nevertheless, several unfortunate situations combined to make the final outcome considerably worse. The first setback came when a fluid leak damaged the engine during qualifying, leading to a Mercedes power-unit change ahead of the Hungarian Grand Prix. The second arrived only moments after the five lights went out on Sunday.
After the race, George Russell admitted that he needed the summer break to recover from a first half of the campaign that had delivered more regrets than satisfaction. His start-line problem was another example of circumstances combining to influence an entire race.
Mercedes explains George Russell’s Hungarian GP start problem
Mercedes initially suggested over the radio that George Russell might have made an error by easing off the accelerator during the start procedure. At that stage, the engine was running at high revs while attempting to generate the necessary turbo boost for the launch.
George Russell did reduce his throttle input while the lights were illuminated, moving from approximately 30% to below 10%. However, that action was not the trigger for the problem. It was the consequence of an engine-speed anomaly that the Mercedes driver was attempting to manage.
Toto Wolff confirmed after the race that there was a technical explanation and that George Russell was not responsible for the incident.
“It looks as though there was another problem. It appears he applied around 10% throttle and the car immediately reached maximum revs. He came off the throttle and it dropped. That is the reason,” Toto Wolff explained. “I’m not happy at all about the number of mistakes that have happened. That is the issue. But after that, he drove very well.”
Speaking later to Sky, the Mercedes team principal added that the situation was unacceptable because of the reliability failures and technical errors the team had committed during the first half of the season. The problems compounded a weekend in which Mercedes had already struggled for qualifying performance in Hungary.
Why George Russell changed his throttle input
Toto Wolff’s explanation matched the account George Russell provided after the race. The British driver said he noticed the engine speed rising beyond the intended threshold and attempted to lower it by adjusting the accelerator. His varying throttle input was therefore a reaction to the problem rather than the reason it occurred.
“I was on the throttle, holding the engine revs, and then suddenly, about four seconds before the lights went out, the engine started revving out of control,” George Russell said. “I was reacting with the throttle pedal, but nothing was happening. The engine wasn’t responding to the throttle.”
During the start procedure, Formula 1 drivers must maintain a specific throttle level to generate the turbo boost required for the launch. They can also monitor the situation through the steering wheel, where a system indicates whether the engine speed is too high or too low, allowing them to react accordingly.
George Russell’s onboard footage reveals that the engine-speed trace was not linear, particularly as the five starting lights illuminated. The irregular behaviour is also supported by the telemetry data.
Telemetry comparison with Andrea Kimi Antonelli reveals the anomaly
A comparison with Mercedes teammate Andrea Kimi Antonelli illustrates the scale of the problem. At the beginning of the procedure, during the additional five seconds of preparation introduced this year, both drivers applied approximately 30% throttle, as expected.
Andrea Kimi Antonelli’s throttle input then remained stable, with his engine speed holding at approximately 12,300rpm. On George Russell’s car, however, the situation developed very differently.
The British driver’s engine began exceeding 12,700rpm and briefly reached approximately 12,800rpm, a particularly high figure at that stage of the procedure. As George Russell later explained, he responded by repeatedly adjusting the accelerator and progressively lifting his foot until he had almost completely released the pedal.
Even that was not enough to stabilise the engine speed. The telemetry indicates that the revs briefly dropped well below 12,000rpm before rising again to approximately 12,600rpm, despite George Russell applying less than 10% throttle.
How the engine problem triggered anti-stall
That irregular behaviour led directly to the second part of the problem. When George Russell attempted to launch from the grid, his throttle input stood at only 9% because he could not safely apply more power while the engine revs were behaving unpredictably. Andrea Kimi Antonelli, by comparison, was at approximately 30% throttle to generate the normal launch momentum.
As George Russell released the clutch and attempted to move away, the engine suddenly lost a significant number of revs. This was probably influenced in part by the fact that he had started with less than 10% throttle.
Andrea Kimi Antonelli’s engine remained at approximately 5,800rpm when the clutch was released. George Russell’s fell to around 4,500rpm, leaving the car without sufficient drive and causing the anti-stall system to intervene.
The incident compromised George Russell’s entire Hungarian Grand Prix. It followed the engine replacement required after Saturday’s water leak and came during a weekend in which his teammate had also faced difficulties, including Andrea Kimi Antonelli’s qualifying grid penalty.
Mercedes encountered a similar issue in Bahrain testing
George Russell revealed that Mercedes may already have experienced a comparable problem during pre-season testing in Bahrain. The fact that his W17 was using a newly fitted engine made the incident particularly concerning.
“It was obviously a brand-new engine,” George Russell said. “I think it was something we had seen at some point in pre-season, but yes, I have no idea.”
Mercedes must now understand why the engine speed rose independently of George Russell’s throttle input and why the power unit failed to respond as expected during such a critical phase. For the British driver, the malfunction added another costly setback to a Budapest weekend already damaged by reliability trouble.
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