I thought my recent experience might just possibly save somebody else a headache!! We just launched for the season after being on the hard since last August. Problem was the Cummins engine would not start. Turned over OK but would not fire up. Traced the problem to the fuel shut-off solenoid that would not open the fuel valve. Once the valve was opened manually, the engine fired right up and the solenoid was able to keep it open until the engine was shut down. Turns out that the solenoid is a double action. There is an initial high current draw magnet that actuates the valve initially for just a few seconds, then the second low current magnet kicks in and takes over the job of maintaining the valve in the open position. After bench testing the solenoid it appeared fine. So, we started tracing wires, checking fuses, and generally trying work out what was up. And, to make a long story short it turned out to be a battery problem. The same battery that had just been "fully charged". The starter battery terminals were in need of cleaning/tightening. There was enough current draw to turn the starter motor but not enough to turn the starter while also putting a large current through the solenoid. So today, cleaned, tightened, and recharged the battery , and the engine started right up. Moral of the story is things ain't always (ever) what they appear to be and a weak battery connection can ruin your whole day!! The good news is it did not cost any money to fix!!