Before COVID I had great psychic powers, but mine and most others around here lost them due to loss of human interactions with humans. How do you expect to get any help with the limited information you provided. Lawn boy had eight different models in 1978 and used at least three different engines. Is it a vertical pull or horizontal pull recoil? On top of that 75% of the people on this forum probably weren’t born then And only about 10% have ever worked on anything that old. Engine numbers and/or units model and serial numbers would help us help you. As we used to say back then, “The ball is now in your court”.