I have a friend with a new mercury control box and cables and he is looking to use it on an older merc motor late 70"s early 80's. On my Yamaha I had to make adjustments to the box in regards to the shifting being pull vs push. Could this be an issue on my friends merc. I will explain to him how to check but I don't want to complicate it for him if this is not an issue with Mercury control compatibility. Thanks for any input