* Kuchar loses momemtum after weather delay * Shoots a 70 for a three-way tie at the top * World number one Day trails by three strokes (Adds detail, quotes) June 4 (Reuters) - Former champion Matt Kuchar surrendered the outright lead with a bogey on the tricky par-four 18th to conclude the third round of the weather-hit Memorial tournament on Saturday, setting up the prospect of a Sunday shootout. Kuchar had stormed a stroke clear of a tightly bunched leaderboard with a run of four birdies in five holes from the 11th but stumbled at the last after finding a bunker off the tee and the right rough with his second to card a two-under-par 70. First-round leader Dustin Johnson (68) was a further shot back in a tie for fourth with fellow American Jon Curran (68), Canadian Adam Hadwin (67) and Argentina's Emiliano Grillo (70), with another eight players no worse than three off the pace. More...