it doesnt have to be a marine turnbuckle, whatever that is. I just got one from home depot. Its like a 3/8" or something pretty small. One ends hooked and the other has an eyelet. You can bend it out if you can find one like that. The eyelet side gets bolted to a small hole on top engine mount. The hook extends down and hooks underneath the crossbar connecting the carbs together. You can sorta see it in this pic.
