New Engine On A Older Drive???

[thedukeryan]

I bought a mid 70's glasstron with a mid 70's 85hp outboard a while back. The seller claimed that it had a newer engine but when I ran the serial number it had a man date of I believe 73. I figured he didn't know what he was talking about. Anyways today I was working on a 75 Mercury 850 85hp outboard and decided to compare the two. After a quick look over it is obvious that the two engines are completely different. For example the ignition pack on the 75 is in the front by the chole while the ignition pack on the 73 is on the drivers side. Also the 73 looks damn near new. Shinney paint, no grease or oil residue, all rubber looks new etc. Overall the 73 looks a lot cleaner and more advanced than the 75. How can one find out the engine year and is it practical to think that the engine on a older drive has been replaced with a newer model? I looked all over and did not see a serial number. I did see a casting number that read 72973. Any opinions?

 

[Chris1956]

Re: New Engine On A Older Drive???

A 1973 Merc 850 will have a battery/distributor ignition. The 1975 may have the 4 coil ADI Ignition system, however, I am not sure. The serial number on the transom bracket will tell you it's age.

The crowleymarine.com site has a parts catalog for those Mercs. You might look up some motors and match up the carbs and ign system