Merc 850 / model #4093045

[Blazeaway]

I know next to nothing about boat engines and this one is mounted on a Starcraft American mod. #16A. It became property of my friend's self storage company, and he gave it to me.

As you may well have already guessed, the mice ate most of the wiring.
So from what I found online this engine came out in 1975.
Is that true?

I was told there was a:
Merc 850E ( Electric start, short shaft, with alternator) in 1974 & '75 only.

Also a :
Merc 850EL ( electric starting, long shaft, with alternator) 1974 - '76

Can any one confirm this or share a link were I might help myself?

Not sure what I've got here.. Or if it is worth investing my time and capital

Any suggestions and thoughts shared would be greatly appreciated.
MLM

 

[Fun Times]

Here will be a parts guide for your engine,

850 (4 CYL.) - 3493913 THRU 4366801

850 (4 CYL.) - 3493913 THRU 4366801

www.mercruiserparts.com

850 (85.0)

4092965 - 4366801

1975

 

[roscoe]

Not sure what I've got here.. Or if it is worth investing my time and capital

get a title and registration in your name before spending a cent.

 

[1960 Starflite]

Plan on a complete rewire. Insulation on wires of that era gets brittle and falls off.
Rotor in distributor is part of shaft, don't attempt to remove or get $200 ready to replace.

 

[Chris1956]

Those were great motors in their day. Light, powerful and compact. If it shows signs of being used in saltwater, you may want to get rid of it. After all this time the salt rots out the exhaust baffle and exhaust covers, and actually makes the aluminum block real brittle.

If it were me and a fresh water motor, I would pull the spark plugs squirt some 2 cycle oil into the cylinders and check the compression.

If the compression is even, and you want to use the motor, replace the engine wiring harness. Be real careful with the distributor trigger wiring, as the trigger is $200+ and a PIA to replace. Also, the trigger could easily be bad by now. You saw the warning about the rotor. They are real brittle and non removeable, and a PIA to replace. Rotors and distributor caps do last the life of the motor when cared for.

You will want to change the gear oil, grease all the fittings, clean and rebuild the carbs and rebuild the waterpump. Put a flusher device on her and start her up with some fresh 50::1 fuel mix. Watch for arcing from the spark plug wires to the block. Replacement spark plug wires are avail. use the OEM style "Tiger Tails" for replacement.

An OEM service manual is best.