Can anyone tell me how to determine accurately whether I have Bravo 1's, X or XR's. A number of business have all told me different !
1998 MerCruiser MCM 502 MAG MPI; 415HP
Is there a site that I can input the serial numbers?
Dave at Fountain has told me they are technically XR'S, before MerCruiser started their advertising campaign and added new logo's in 99/00.
Any feedback would be appreciated.

likely than not with your 502 Mag MPI's you have Bravo 1's. Why, other than a real lack of smarts, anyone would tell you they are XR's is beyond me. You can take the serial numbers to any Merc dealer and they should be able to give you an answer. Lots of clues, prop shaft size? gear cut? Pull the back cap and take a look see. Pretty simple deal, no reason for any builder to hook 502 Mags up to XR's. Not saying a former owner might not have done the change.

Post the serial # on drive I can check it for you

Thank you Clustergear;

Drive serial #'s
0L86936
0L18635

I think you might be missing one number. Both come back serial not found. If you can't read the numbers post engine or transom ser#. If they came with boat the number should come up under product history

My book says standard Bravo 1,,Im saying that because I didn't see anything else made starting with OL

Didn't all xr's have the larger prop shaft? And the brovo 1 and 1xz had the 1 in

XR's are 1.25 inch prop shaft

Only definitive way is pull the top cap, take picture of gear teeth(its tough to get the angle but it can be done), post pictures, reassemble.

There are too many what if's on a boat over 10 years old. The part numbers tell you what it "was" - if they ever broke, who knows what was put back in.

The X family started @ s/n OM