Identifying v6 3.0 250 with no serial

[r_al_sim]

Hi can anyone help I'm looking to identify an engine with no serial number i've looked at every core plug I can see and can't see a number, I've attached images of all the numbers I can see on the block and leg.

I need to buy a lower unit for it as it doesn't have one and need to know what ratio and size to to buy for it
https://goo.gl/photos/uJpFan6ZK1DQZYTV8

If the link doesn't work I'll try and upload them to here

 

[Fun Times]

Using the wiring harness part number 84-825763A4 I was able to find where that harness fits. According to the parts diagram this part number is listed for a similar engine year/model/serial number range yours may be (1998 - 99). http://www.ebay.ca/itm/1999-Mercury...ash=item1a122ff318:g:yUUAAOSw2GlXFpeq&vxp=mtr

The serial number range for around 1995 - 1999ish looks to be serial number range 0G129222 THRU 0G760299 .... Though 0G760300 is still 1999ish. while > THRU 0T408999 is getting up into 2000+.

But unfortunately for finding a part number for what lower gear case housing you need still appears a little challenging without knowing your serial number range as they list 2 options looking over the parts diagram selections...Such as GEAR HOUSING CHART(S/N-0G437999 AND BELOW) or GEAR HOUSING CHART(S/N-0G438000 AND UP).

http://www.iboats.com/MERCURY-250-3-0L-EFI-1996-1998/dm/view_id.1702704
http://www.iboats.com/MERCURY-250-3-0L-EFI-1998-2001/dm/view_id.1702705

You most likely could search online/eBay your engine year/model and locate a lower gear case housing somewhere if desired.
You'll also need to know what shaft length you'd need to use to fit your boat, etc.

 

[Faztbullet]

ECU dates it as 1996/97...does it run and why is unit missing??? SEI is you best choice..

 

[Dukedog]

ECU dates it as 1996/97.....

weird?... harness dated 2000.