Rambling Roos

Frank, you are right on target. That is exactly my scenario. The thing is, I replaced the LN Duvac with a Delco 28si, which also says it is Duvac and it has the ignition excitation function like the LN. It still doesn't seem like it should be feeding anything back over the ignition line, but I'm convinced that is what is going on, and with your experience, I'm also convinced that the right solution is the diode. I've already got some in my Amazon cart 😁. Again, thanks for your insight.

Thanks for all the good suggestions. In fact, I tried basically the test that Frank proposed (disconnected before starting because I can't safely get to the back of the alternator while the engine is running). Lo and behold, that was the problem. So now, I need to figure out why there is current feeding back into the ignition circuit. I can't see how that would be, unless there is something simply wired wrong inside the alternator. I'll consider the diode if I don't find some other cause. The curious thing is that I expected the alternator to not generate anything since it didn't have the ignition trigger, but I was getting 14+ Volts out of it (amperage is a different question - no convenient way to measure that). In any event, I have a workaround for now, and a long-term fix (diode) if necessary. Thank for the help, folks! --Roger

Hello, Monacoers! We have a 2007 Beaver Contessa 42’, that we purchased 3 years ago. This one is equipped with a Cummins ISL 400. I’m looking for help in locating the fuel shutdown solenoid. This part is only incidental: I recently found that the alternator wasn’t pushing enough voltage to maintain the chassis battery. In the process of resolving that, I also did some cleaning in the engine compartment (bad oil leak that I also have yet to track down). The cleaning may be the cause of my current problem. After the repair, we started up the engine and confirmed that the alternator is fixed, but then found that we could not shut down the engine. The ignition was clearly off (and all auxiliary power was off, so pretty sure the ignition switch is working correctly). That led me to search for the fuel shutdown solenoid, or the fuse to it… but I came up empty-handed. Eventually, I pulled the fuse for the ECM which finally killed the engine, of course. However, I now have the question: Where the heck is the shutdown solenoid? I’ve looked on Cummins QuickServe and this engine appears to have the fuel rail system, but in none of the diagrams do I see the shutdown. Nor do I find any fuse (in the rear bay or in diagrams) that is labeled for the fuel shutdown. I must be missing something, because my understanding is that there really HAS to be a fuel shutdown somewhere. I’ve looked on and around the fuel rail and other than the feeds to the injectors, the only thing I find appears to be the pressure sensor. EDIT: On the Beaver FB group, someone told me that ECM controlled engines don't use a fuel shut down valve, so that would explain why I can't find it. Now the question is what else could be keeping the engine running with the ignition off? Can anyone offer guidance on locating the fuel shutdown? Or any other ideas on the cause of the engine failure to shutdown? I appreciate your help! --Roger 2007 Beaver Contessa Bayshore 42’ Cummins ISL 400, Allison 6-speed