A lack of power is the root cause of problems with the Honda power, according to McLaren racing director Eric Boullier. 

The Japanese manufacturer's problems continued at the last race in Russia, as an ERS failure meant Fernando Alonso was unable to take the start, grinding to a halt on the formation lap. 

As Honda frantically trying to find lasting solutions, former Lotus boss Boullier claims there is not one area where the power unit is as good as their rivals. 

"Formula 1 at the moment has a downside," he told Austria's Speed Week. "The gaps between teams has increased even more.

"[But] An engine that is more powerful is also more efficient, with better consumption and stability.

"The more powerful engines have all the advantages, and our engine combines all of the disadvantages."

Boullier also warned McLaren's engine partner not to get bogged down with short-term fixes, believing some focus needs to be shifted beyond this year.

"2017 is still under development and the rest is the responsibility of Honda," he said.

"But Honda must start now (to look ahead). Mercedes, for example, already has an engine that will run in 2018," the Frenchman added.