[JPonLKN]

Assuming everything is tight, and there are no worn connections, loose nuts, and bearings are in good condition, simple alignment of the front wheels is likely all that is needed. First, lift the front of the cart and see if there is any free play. Spindle, hub, steering, etc. If not, slight negative toe would help...1/8" to 1/4". Set the wheels straight, find the center line of the tires, measure the distance between the left and right front centerlines at both the front and rear of the tires across the width of the cart. The front measurement should be slightly less than the rear measurement. "Toe'd in" I will assume you are toe's out currently, hence the high speed squirrelyness. Just need to adjust the tie rods equally on both sides to get to the slightly toe's in condition.