While it makes sense to buy oem when needing electronics.
It doesnt always for the rest of the outboard.
Just as at the pharmacy it makes sense to buy the name brand if it alone works well 285 dollars,and the 12 dollar generic if one can make do with it.
Mechanics however are not required to ask,but doesnt hurt if you do.
A rebuild , I was quoted a price I did not like went online found the pistons(better ones) and needle bearings $11 each,and cut my $ spent in half,actually getting better high preformance parts in some cases.
Lower units used bring more than these new,one reuses the main shaft.
Just thought anyone needing a lower might like the link.
http://www.sterndrive.cc/
Regardless of brand when referring to older motors the patents are long out of date,and sometimes parts scarce due to wanting the price up,or a desire to control that end of the market or just total lack of concern,you should after all buy a new one.