Replace the 4x6 saw's motor with this one from Grizzly.
G2903 Motor 3/4 HP Single-Phase 1725 RPM Open 110V/220V
It's a bolt-on replacement for the original, but it runs cooler and has gobs more power.
I had to buy one of those after my original motor burned up. It has completely transformed the saw. I cut 3" x 1" stock into 3" blanks using the saw, and it gets it done quickly and without problems.
An even better option would be a bigger saw with a hydraulic downfeed and coolant system, like this one. But of course, it costs more.
G4030 6-1/2" x 9 1/2" Metal-Cutting Bandsaw