controllerのlimitの使い方

findの後に->limit(n)で繋げます。

public function index()
	{
		$this->viewBuilder()->layout('my_layout');
		$now = date("Y-m-d H:i:s");
		$params = array(
		    'conditions' => array(
		        'forecast >' => $now, 
		    ),
		);
		$marunouchis = $this->Marunouchis->find('all', $params)->limit(3);
		$yokohamas = $this->Yokohamas->find('all', $params);	
		$this->set(compact('marunouchis'));
		$this->set(compact('yokohamas'));
	}
}

$paramのconditionsに追記するとエラーになりますね。