Takes me 3-4 tries to start our Caterpillar 3126 engines after they have sat overnight. Once started they run fine. We wait extra time for the preheat--volts back to 13.3. They try to start--getting to 300-500 rpms and then die. Cat has no answers. Anyone have a clue?? W Macauley Lucky Dog Grand Banks 42 Europa--850 hours Vero Beach, FL Sounds like fuel delivery pressure problem probably caused by an air leak. I would put a gauge on the delivery pump output side let it sit and try to start it see if pressure comes up and stays up. Brian Palmetto FL