8906 vs 8907?

[Llanorider]

Okay I know it's been asked over and over, BUT...if you're trying to buy a used K&B 3.5 outboard engine from someone who doesn't have the where-with-all to mic the darn piston sleeve OD or crankcase ID to let you know if it's .750 or .765, how else I can I distinguish if this engine has the 13mm crankshaft and larger crankcase ID/sleeve OD measurement?

I've heard that possibly the serial number could help, but then again I think I read somewhere in this forum that the SN wouldn't be of any use in answering this question.

Is it just a gamble until I get the engine in my hands to actually do them measurement myself? I know...don't buy "used" stuff. Please don't answer with that!

Thanks.

serial number is j0032012

[MECOA]

Sorry but the SN won't help. The 13mm cranks made prior to 5 years ago had 13 stamped on them when you look in thru the PTO side of the crankcase. All 13 mm crank engines were originally supplied with the .765 cylinder, but it is possible that the later crank was installed by a former owner.