Late Model vs Early Model...easiest way to distinguish?

[Llanorider]

Somewhere in this forum this question is probably asked and answered, but I couldn't find it after taking a quick run through the various topics.

What is the easiest way to distinguish between a late versus an early model K&B 3.5 engine? I know you can measure the OD of the sleeve or the ID of the crankcase to see if their .765 or .750, and I think this is necessary for sure with the 8906 and 8907 engines. Is there any other way to easily determine this with the 8906 or 8907 engines?

Given that the 8935/8950's are newer K&B engines, do they all have the 13mm crankshaft or do they also come in an early/late model design and therefore also require that the sleeve or crankcase be measured to determine their origin?

I don't know if it's me or are there a lot of K&B owners out there that are confused on this. I get what I believe are some weird responses to this question, and I'd just like to know the facts on this matter once and for all.

Thank you.

[MECOA]

These are all the major differences...

Changes were made to the crankshaft.
Early 12mm, and all later engines had 13mm.

Very early 3.5's sleeves had a smaller O.D. Crankcase I.D. and sleeve OD must be checked.
Early size is .750 -- Late/current size .765

Early 8906 had a clamped in prop shaft assembly.
New style will not fit. You must replace the entire lower unit

The early 3.5's use a short glow plug and the later one use long plug.

[Llanorider]

Okay, I had read that on your website, and I assume that this definitely applies to all of the 8906 models; but does it also apply to the 8907 models? In other words do I need to verify whether an 8907 is "early" or "late" model design?

Additionally, can I assume that the 8935/8950 engines are all "late" models with the 13mm crankshafts since they are the newer K&B 3.5 engines?

Please let me know.

Thank you.

[MECOA]

8907, 8935 and 8950 are all late style. I can not say for sure about ALL the 8906's.