have an 82 n7 which also starts hard. block heater works well, but when not near the farm either is the only way to get her going when say 40 f or colder. a couple tricks though. as mentioned above, slow down the engine 700-800 is a good speed, it makes a big difference. also the either injection only workes when you are starting the engine with the key, but after it starts firing, you can let out the clutch and then turn the key and push the either button. the starter does not engage but the either injection does. works good to get it to take off after initally firing and running on a few cylinders. not sure if the f's have a clutch but if they do, it should work. this also works on our 7040