Diversified industrial manufacturer Eaton Corp has announced a 35 percent rise in second quarter earnings, after sales were boosted by acquisitions, but has reduced its full year forecast due to the impact of higher oil prices in several markets.   The Cleveland-based company said net income rose to $333 million ($2.03 a share) from $246 million ($1.64 a share) a year earlier. Sales gained 32 percent to $4.28 billion over the same quarter last year.    Net income in both periods included charges for integration of acquisitions.