I have 500 amp Jump Pack and it will start my Honda 3000 generator, but you need more for diesel.
Those jump pack delivers boost for few seconds and then you need to reset them.
When you need to wait for Glow Plugs to warm, the jump goes into idle by the time you are ready to crank.
Good item to have as I used it as cellphone charger as well when I was on the beach, but I've got my as a gift for participating on other forum (!) and don't think I would spend the money on it.