I have a Evinrude YACTWIN Boat motor, model 3533A, Seral Number R7004. What year I it?

Hey Jan,
The model number/serial number should be on plate attached to the engine mount...You need the model number to determine year.
Outboard Motors Boat Parts Marine Engines Inboard Boat Motor

Bruce,
Do you have the serial number of the motor? Reason I ask is twofold. Evinrude started using this model number layout as of 1980. Having said this, something is not making sense with the location of the "N" in your model number. Those last two letters as of 1980 are the year. Here is the chart. Letter on top with corresponding year below it.

I N T R O D U C E S
1 2 3 4 5 6 7 8 9 0

So... Example
1980= CS
1990= ES
2000= SS
2010= IS

You have E8RLNR which breaks down as:
E= Evinrude
8= 8hp
R= Rope start tiller steering
L= 20" shaft
N= 2nd year
R= 4th year

I would expect to see the N in the last spot:
1982= CN
1992= EN
etc.

Serial number is another way to identify the year.
This may hep point you in the right direction. Hope it helps.

marineengine.com/parts/engine-model-guides/omc-johnson-evinrude-model-number-guide/omc-johnson-evinrude-model-number-guide-00004.html

Regards,
Fred

going by the model number 6RCRM the year is 1984
here's a link to the codes

http://www.iboats.com/basics/johnson-evinrude-80-later.html

Rob, AQABVA71K899 does not seem to come up as a valid # for referencing engine. Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
Outboard Engine Serial Number Year Match up
Evinrude Outboard Motor Model Numbers
EVINRUDE OUTBOARD MOTOR MODEL YEAR LOOKUP GUIDE 1913 1979 MASTERTECH MARINE

Evinrude used a shift mechanism located in the lower unit that is actuated by a rod up to the linkage in the motor housing. It could be stuck anywhere along the way or the gear that shifts on the shaft could be immobile due to rust and corrosion.

You may want to find a blowup of your exact model via a Google search. Then starting from the top look for your problem. be sure to mark the position of anything adjustable so you can at least get it back to the original position when you reassemble it.
Find 1985 40hp Johnson Evinrude Outboard Motor Parts by Model Number

Hello,

To have the year of your engine, we'll need the engine typenumber, not the serial number...

look here

http://www.iboats.com/basics/serial_number_year.html

The Manual Store also has some useful boat motor model year lookup data:
Boat Motor Model Year Lookup Guide