NEW ORLEANS The 49ers are still winning, Colin Kaepernick's hand is still hot, and Jim Harbaugh is still keeping his lips sealed on the identity of his starting quarterback.
Kaepernick made his second straight start Sunday in the thunderously loud Superdome and seemed to be at his best when the crowd was at its most raucous. He completed 16 of 25 passes for 231 yards in a 31-21 win over the New Orleans Saints.
Kaepernick threw a six-yard touchdown pass to Frank Gore and faked out half the Saints' defense and half the crowd on a keeper for a seven-yard score in the first quarter.
The 49ers (8-2-1) opened a 21/2-game NFC West lead over Seattle, which lost to Miami.
Kaepernick and the 49ers were particularly effective on third downs, converting 6 of 13, many on third-and-long situations when the Superdome was at fever pitch.
Three of those conversions came on a critical 16-play, 85-yard drive spanning the third and fourth quarters. The drive lasted 9:28, and David Akers' 27-yard field goal put the 49ers ahead by two scores.
"I think he did a really nice job of extending plays," Harbaugh said of Kaepernick. "We were kind of cut off at the knees with penalties in the first half, and they were resulting in some big (conversions)."
Harbaugh would not say, however, whether Kaepernick had done enough to earn a third start. He has said that playing the guessing game when it comes to his starting quarterback gives him a competitive advantage, and he continued to play that game Sunday.
"We'll address that later," he said.
Harbaugh did say that concern over Alex Smith's health played a big role in his decision to start Kaepernick this week. Smith suffered a concussion Nov. 11, and Harbaugh noted the 49ers' regular starter still was dealing with effects eight days later.
"I've just had some bad experiences not going to put a guy back out there who had symptoms like he had," Harbaugh said. "They were serious enough. Now he eventually got cleared. But the thought was to rotate him back into the action but not all the way to the front line. Thought that would give him a chance to get cleared up completely. That was the rationale."
Smith received his final post-concussion clearance Saturday. As one of the 49ers' captains voted on by teammates at the beginning of the season, he participated in the pregame coin flip.
Afterward, he spent the game on the sideline, listening to the play calls through his helmet when Kaepernick and the offense were on the field and sitting with the receivers on the bench when the defense was playing.
Smith said he hadn't been told who the starter is moving forward.
"No idea," he said. "Honestly. Don't have any idea."
Kaepernick was not as sharp as he was in his starting debut last Monday against Chicago.
The 49ers' defense had the biggest plays of the game two interceptions that were returned for touchdowns. Kaepernick, meanwhile, threw an interception in the second quarter and nearly tossed another on a pass to Randy Moss in the end zone that would have squandered the 85-yard drive.
But he was sharp on many critical passes, and for the second straight week, he pushed the ball downfield. He had completions of 45, 40 and 26 yards and also scrambled once for 15 yards.
Tight end Delanie Walker, who had a game-high 81 receiving yards, said that when Kaepernick was running the huddle amid the Superdome chaos, he certainly didn't seem like someone making his second NFL start.
"He plays like he's been here for a while," Walker said. "That just tells us he prepares hard every week and he comes out and he's ready to play."