Answer:
The February Revolution in 1917 did not affect it at all, because the new Provisional Government kept it going just as the Tsar had done.
The October Revolution eventually ended Russia's participation in the war when Lenin entered into the Treaty of Brest-Litovsk with Germany. After that, Germany moved the military forces that were fighting the Russians over to fight the French and English on the western front. That increase in military force could have won the war for the Central Powers but then the United States entered the war and added its forces to the Allies.