Cat 246 Won't Start

I can't get my Cat 246 (5SZ00786) to start. It turns over, but it just cranks. Prior to this, it was running just fine - no issues. I did refuel it last time it was running (I refueled it while running since I use the machine's battery to power my diesel pump), but it's the same diesel I've been using.

I do suspect it's a fuel issue, but I'm unsure of exactly how to troubleshoot it beyond replacing the fuel filter. The filter has only about 150 hours on it, but it's not ran too often so...

Cat 246 Won't Start