1978 mark twain 898 (350 now). iam guessing its the lower shift cable. runs good, goes in forward fine. stalls when you go into reverse gear. boat was sitting for a few years. we just dropped a 350 in too replace the old 305. other then what i have allready read about how too replace the cable on here, are there any other pointers or tips? or could i have a issue somewhere else?