I hate to say this but 20hrs or 200hrs if it is not warrantied it is a used engine.
To many threads in the beware section starting out "I bought this low hour _____
and ran it for 30 mins, blew up, tore it down to find xxxx......

So $7000 is the going rate for a used 525sc.

its always a risk buying a used motor..i agree. been there done that. bought one motor that blew up first time in the water. had another one that got 14 races out of before selling.
at any rate if the motors are true 20 hrs never rebuilt, i think its worth the chance. if they were rebuilt by any one else other than Merc, than I would offer much less. or maybe even walk away

Merc put lead wire seals on the rear intake bolts. So if the engine has never been apart they should still be there. That could be a clue if they are 20 hour or 20 hour since rebuilt.

geez . no wonder mercury engines sre like gold . i think there are some verry repetable engine builders out there besides mercury . just my opinion though

geez . no wonder mercury engines sre like gold . i think there are some verry repetable engine builders out there besides mercury . just my opinion though

yes, there are many reputable engine builders out there. there are also many bad ones. but the topic of this thread is what are the 525sc worth?

IMHO...having owned merc engines and custom built engines.
If I had the choice between a merc racing 525sc w 20hrs or
any other custom built 525sc for the same price, Ide take the merc hands down.

The Merc 525SC is a great engine. Hand assembled and balanced at Merc Racing. They are also very easy to duplicate and make the same or more power without spending a lot of money.
I would say a big factor is who is did the rebuilds and what exactly was done and replaced.