Maurice, It looks like what you have is a 1970s Fox 15X....a fine little engine and will give good service using the right fuel (5% nitro, 29% castor and the balance methanol) It is important to use the right prop as well, a 8X4 is a pretty good size for this engine, 7X6 also works well.....Four turns on the needle will generaly get it running..
Regards, Phil Bare