Heres some photos that I hope will help. The thick green M wire supplies power from starter relay, After going through four electromagnets it attaches to E terminal. The smaller wire from four electromagnets also attaches to the E terminal (Two of the brushes and the white wire also attach to E terminal. They may go on different screw but there is a metal band connecting them ). This is how on electric starting all eight electromagnets are used.
 The F terminal is a small green wire going to voltage regulator. The voltage regulator GROUNDS it to produce voltage back at the E terminal. So if you put a ground jumper from engine case to F terminal you have bypassed the voltage regulator (briefly for testing  )and have to keep RPM’s low to avoid high voltage hurting things. The manual states keep it under 1800 RPM. So anyway voltage should be around 14 volts at 1800 RPM ( DC not AC.) It is not a true DC voltage so some meters may be inaccurate hence I just used a light bulb on mine as in picture. 
 Small green wire unhooked from F terminal (motor off), should show it’s grounded or very low ohms, if not clean contacts in voltage regulator, caution there is always 12v in voltage regulator even if switch is off. 
 Use electric starter feature to start motor as it applies 12volts to the charging field coils
 
 

thanks very much DaveHunter, that is very detailed and most helpful.

so to be clear, the wire I have indicated with the red arrow goes to E terminal? Right now its on the F terminal with the small green wire. 

No / that tiny black wire you have indicated goes with the small green wire (F terminal)

 
This might be a better photo, in that rectangular space at 11 o’clock two wires come out . A fat one that goes with the big pale green wire and a small wire that goes with the small dark green wire. I’ll be in the shop some this weekend & can take better photos if needed

I think that will do,thanks again. One thing I am thinking but would have to double check is I thought I had continuity between the 2 small wires coming from the coils.Not sure if that's good or bad,but I assume not good but again will double check that.

Hi all, well I failed at getting this sorted before christmas but here we are. Worked a bit again on this tonight and this is what I have found. According to the Yamaha manual, to test the field coil you connect a meter to terminals A and F and it should measure 4.8ohms as seen in pics 3. As seen in the pics it measures what it should. Curious thing is the positive brushes shouldn't have continuity to the yoke but they do. The brushes are connected to one of the field wires on the A terminal, that field wire has continuity to the yoke,pic 1 as does the other field wire pic 2. Does this mean I have a short in the field coils to ground?


 

Just tested mine, field coil wires disconnected from anything had 5 ohm between them and no continuity from either side to ground.  
 The green wire coming down from voltage regulator to F terminal had 10 ohm to ground
 Everything hooked back up and .3 ohm from their connections to ground.
Hope this helps
 

thanks DaveHunter, will check those numbers.

 Alright all,took a look at this again tonight and armed with DaveHunter info from last post,here's what I found. Image 4 shows tester on the field coils wires which between them has 4.7ohms but what I don't like is pic 1 and 3 shows field wire to ground which has continuity which I don't think is correct.Any thoughts?