Yes the worm does fit the known 288 pump but the new o e m Worm Drive is a fraction bigger then the OEM worm drive with that pump I believe the pump that I have that was sent to me uses a brass Worm Drive and he must have sent it to me by mistake I was hoping someone had more knowledge than me and could recognize the pump that he sent meAm I missing something here?
You have a supposed 288 oil pump second hand, a new worm drive and a pump known to be 288.
Can you not compare the two pumps and see if the worm fits the known 288 pump?
Maybe someone slipped you a 61-272 pump by mistake?
I reached out to the man that I bought it from he is very knowledgeable in chainsaws and he thinks he might have accidentally sent me a 181 SENot sure, but I believe the brass and plastic worm gear are interchangeable.
I believe I replaced a screwed up brass one with plastic on one of my own.
The part number on the worm bag is correct for 281-395 saws.
I can measure the bore on a few pumps I have here.