i have a 77 model 2440 with the 219 4cyl diesel that i just bought. its been sitting for a while but runs good now, shows 1000 hrs. question, what would cause it to rev high to max rpm when first starting it, cold or hot, throttle lever closed, then immediately slows to normal. only lasts 3 seconds. have any ideas?? this is scary when cold and i think is not good for the engine. thanks for any help. injection pump??