300XS serial number location on powerhead

[Maxdvr]

Looking at a pair of 300XS to purchase, serial numbers appear to indicate 20" shaft. ( 1E001988 & 1E001989 ) Engines have 25". I'm trying to locate the serial numbers on powerhead to ensure that they match. Where would they be found? I'm not finding a freeze plug. Behind ECM?14-snL.jpg13-snL.jpg4.jpg

[EuropeanAM]

Black painted powerheads usually had a white decal affixed to the STARBOARD cylinder head (facing you if standing on the STB side of the powerhead).

Earlier models had the serial number stamped into the engine block at the block mating surfaces on the PORT side.

No welch-plug identifiers on these.

Definitely left the factory as 20" models.

[Maxdvr]

Thanks Don!

[Maxdvr]

Would the part number 897906 015 indicate a PCM for a 25" engine? Does the 20" PCM have a higher rev limiter?
4.jpg

[Savage]

No.

[EuropeanAM]

897906-15 is the 25" PCM Calibration according to the Parts Catalog. The Service Manual shows a lower WOT RPM limit for those models in Section 1-A.

CDS can be used to determine if that is actually the case.