I have a Scag SMWC-61A with a Command Pro 27 Kohler engine. Recently, when I first start it up, after pulling choke back, the engine will not throttle up to full power. It stays like this for a minute or 2, then all of a sudden, it kicks up to full power. At 1st I thought it may be a fuel pump. This Scag has 2, one on each side under each gas tank. But when I change tanks, it still does it at start up. Changed fuel filter. Not solution. Do I have a carburetor choke problem? Anyone have any suggestions?