if your motors running, the green wire splice should be OK.
the tach gets its feed from the CDI on the blk\purple wire. most likely the problem is at the tach connections end.
At the tach - verify the brown wire has good ground, the red\blk wire has 12V and the blk\purple wire is connected to the TD terminal.

Update...

Tach is now working...my bad. I did leave one connection loose, and it was the loose dangling wire in the left engine bay. I checked 3-4 times and couldn't find anything to plug it into. Well, the 5th time, I found a loose wire buried behind the fuel filter...connected the two, and now it works :).

Thanks all to your help!


Lessons learned:

1) You can do a simple splice on the green wire, and it will work fine... No need for special connectors, just some heat shrink tubing...

2) Patience...

Bo