* Engine, power systems maker posts Q3 profit of $1.44/shr
* Wall Street expected EPS of $1.41
* EPS lifted 11 cents by one-time benefit
* Sales fall short of Wall Street view
* Shares down nearly 7 percent (Adds analyst comment, updates shares)
CHICAGO, Oct 26 (Reuters) - Cummins Inc (CMI.N) reported a big jump in its quarterly profit on Tuesday and raised its full-year forecast, but the engine maker's sales came in lower than expected and its shares fell nearly 7 percent.
The company said its profit tripled to $283 million, or $1.44 a share, in the third quarter, from $95 million, or 48 cents a share, a year earlier.
That was three cents higher than the $1.41 a share profit analysts expected, according to Thomson Reuters I/B/E/S.
But the results were lifted by a tax refund in Brazil that added 11 cents in earnings per share to Cummins' bottom line.
What's more, sales rose only 34 percent to $3.4 billion, short of the $3.6 billion in sales analysts expected.
"Components looked like a bit of a disappointment," said Ann Duignan, an analyst at JPMorgan Chase. She said the problem appeared to be both lighter-than-expected sales at the unit and single-digit margins that were "worse than expected.'
The company did not mention specific geographies, but said sales were strong in emerging markets where commodity prices are driving a mining boom.
Cummins said it was raising its full-year forecast for earnings before interest and taxes to 12.5 percent of sales estimated at $13 billion, up from a previous outlook of 12 percent.
Shares of Cummins were down 6.9 percent at $87.95 in trading before the market opened. (Reporting by James B. Kelleher; Editing by Lisa Von Ahn, Dave Zimmerman)