Go back and re read post #2..It's a 3.1.Sachs chainsaw model # 112, 113, or 114...Bore 45mm, stroke 32mm, 51cc, 3.09875 cubic inches...Muffler bolt hole pattern is abput 1.5 inches, same as ALL the current Sachs based 4.2 engines sold today...
I have one in my hand.