Aftermarket lower unit, how do I know?

[FabricGATOR]

I first heard of aftermarket lower units here about a month ago thanks to CaptSolo.

Then I started to look into it out of curiosity of what happens when you fit this to your engine and what water pump do you use from then on etc... again, just curious.
I called SEI in Oldsmar (Tampa) Florida and spoke with them and all OEM parts are interchangeable, blah blah blah. It is a clone of OEM built to their specifications. Some say it is great and others say they would not go out the inlet on one installed. Claims of short life and catastrophic failures.

Now I remember that when I was pre purchase inspection that I noted that it appeared that one engine lower unit had a newer case, I ASSUMED that my buddy Doug may have hit bottom and broke the skeg, he would want it repaired out of pride, function, do the right thing, etc.
Now that is not to say that someone didn't give him a real good deal on a new lower unit.

How can I tell if my used boat is fitted with an SEI lower unit?
For all practical purpose I believe they look the same...

[fairdeal]

very interesting.

I "knew of" SEI but sort of assumed they were just rebuilders - plenty of scrapped LUs available as starting material.

But looking at their website - seems they are buying "new" component parts from Asian suppliers

Of course Yamaha outboards - just like automobiles - are not entirely created from metal ore inside a Yamaha building.
rather "assembled" by Yamaha - using the output of scores - maybe hundreds - of sub-suppliers.

could the sub's agreement with Yamaha allow them to sell the identical casting to SEI? even including the "molded in" Yamaha part numbers?

is it possible for Yamaha to have an enforceable "ownership" of their LU casting shape - preventing it form being "cloned"?

fascinating questions...

[TownsendsFJR1300]

Dunno the answer BUT, if it was an SEI unit, at THIS POINT, your not going to yank it if it's working fine...

Agreed with Fairdeal, there's many OEM LU's out there. I'd think it'd be cheaper to rebuild one of those than start with another NEW housing..

[throrope]

Years ago I made the mistake of rebuilding an engine on a german sedan. Instead of buying OEM pistons for $200 each, I went with aftermarket at $200 for the set. When I compared the original with the aftermarket, I found exactly the same stampings and numbers.

I once ordered a reconditioned starter for my '94 Astro. The box contained a shiny squeaky clean part and on close inspection I realized it was never bolted to anything.

Often "aftermarket" is just another way for factory making the original parts to move more product.

[rodbolt17]

having used SEI on many applications from jonny/rudes,yamaha,and merclosers I cannot complain.
they seem to work well and the warrenty is good.