UPDATE 1-Ameren Q3 profit beats, trims FY09 core EPS view

* Q3 adj EPS $1.16 vs est $1.03

* Revenue falls 12 percent to $1.82 bln

* Sees FY 2009 core EPS $2.70-$2.90 * Sees FY GAAP EPS $2.57-$2.77

Oct 30 (Reuters) - Ameren Corp (AEE.N) posted a third-quarter profit that comfortably beat estimates, helped in part by lower operational and maintenance expenses, but the power company narrowed its 2009 earnings outlook.

The company trimmed the top end of its 2009 per-share core earnings outlook to $2.70 and $2.90, from its prior view of $2.70 to $3.05.

Ameren cited reduced sales due to much cooler-than-normal third-quarter weather and continued weak economic conditions.

Analysts on average were looking for full-year earnings of $2.71 a share, before items, according to Thomson Reuters I/B/E/S.

For the quarter, the company posted a net income of $227 million, or $1.04 a share, up from $204 million, or 97 cents a share, a year earlier.

Excluding items, Ameren earned $1.16 per share, while analysts on average were expecting earnings of $1.03 a share.