Is all serial numbers related to engine's serial?

No , individual part serial numbers are not directly related to the engine serial number.

But for most "recent" engines  (ones produced since the advent of the electronic engine serial number database at the factory in Austria) it is possible for us to look up the 'original' serial numbers of most of the major engine sub-assemblies. (NOTE: This info does not reflect if the engine has had any of its original parts changed out for maintenance or repair!)

None of the earlier engines have any of this data recorded, all we know about older "pre-electronic-database" engines is the date of production.

Back to your question: Your engine 7703416 originally had a fuel pump assembly serial number 15.0097

(If your engine logbook does not indicate that the fuel pump was ever worked on, you can be reasonably confident that you have fuel pump serial number 15.0097 ...)

I can also tell you that 7703416 was produced 02-Nov-2015

Engine Type: ROTAX 912 iS SPORT

Engine Version: 912 iS2 Sport

Model Number: 359120510

Original Factory Configuration:

• Version 2 with clutch, i=2,43
• without vacuum pump drive
• without air guide baffle
• with screw connection metrical
• Fuel pump metrical
• with engine truss
• without exhaust system

Thanks a lot for your fast response. That was a huge help, and it looks like we are not affected by the fuel pump bulletin :-)

Kind regards, Claus