Thanks for the tip. I'm gonna try running on reserve this weekend. runs fine with a full tank in the garage, however seems to run rich (blueish black smoke) any ideas?

 

On those old machines that seem to run rich, it is usually the slide needle and slide needle jet worn out.
Not really much you can do about it but replace them. you can do some adjustments, but the problem is still there, and will always be troublesome till their replaced.

 

It has been a long time since I have seen one of these but I think you can take the tank out and take it to a good automotive radiator repair shop. They should be able to drill and install a new pickup tube. Just cap the old one so no water can get in the tank.