One definite reliable means of slowing/stopping a diesel is to block its air input. It even helps you hold the stopper in place till it dies. This is one of the few good ways to stop a diesel that is running on its own lubricating oil fumes (or a leak).
I like diesels fine, especially in our previous Mercedes Benz type autos and our Dodge Ram but personally prefer propane for backup generators, especially fixed ones that aren't going to be moved a lot. I find them more compatible for short runs with fewer maint concerns.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]