150 HPDI serial numbers

[1st grady]

I am trying to purchase a boat with dual 150 HPDI motors but the serial plates are missing.(glue spots but no tags) The surveyer called Yamaha but they would not tell him where the numbers are located elswhere on the motor. Does anybody know if and where the serial numbers may be located on these motors? I am trying to close this deal but this is creating a drag on the sale. I need to insure these are legit motors.
thanks
BH

[boats.net]

No the tag on transom bracket is the only place the serial numbers are marked.

[ressiv]

if they are 4stroke engine's..you might take a look under the distribution-covers???
greetings:
jan