trying to find out the year of my merc. 500

[B-Bean479]

I also bought this boat with no knowledge on the Shape of the motor. All the info I know is it was last reg. In 2008 set in a field after that until 2013. Has good compression. Started is good. Timing is good. Tore the lower unit apart cleaned it up everything seemed fine there. Has some kind of weird spark plugs. I tried to get spark by grounding it out nothing happened. It did not have a throttle and shifter when I got it. I had a Tohatsu one laying around the power cables don't match the motor. Where can I find these? I also am looking for a wiring diagram or manual. All the wire covers were brittle and falling apart. I am new to outboard motors. Thanks guys. Serial number 4074716

 

[MTboatguy]

Looks like it is probably a 1974

 

[B-Bean479]

I also am trying to figure out why I'm not getting spark. I did not get the throttle that came with the motor. I am using a 90's model tohatsu shifter and I am hard wiring it straight to the motor. I have power and can turn the key and get the motor to turn over. But no spark. I think it may be the stator? Distributer? Ignition driver or coil. Maybe the switch box. Thanks