AC-816 (MTF Newbie!)

Hey guys, brand new to MTF!!! This site rocks! My father and I are trying to get my grandfather's 1984 Allis Chalmers model 816 tractor up and running. We are running into a few issues maybe anyone can help?

1) In order to start the tractor we need to "jump" the solenoid. We tried to replace the solenoid but still didn't help. I know that there are three safety's on the tractor (Neutral, PTO, and Clutch). We tried to bypass that Neutral safety.... How exactly would we do this? I think when we were trying to bypass this safety we might have also shorted something out because one of the leads accidentally his something it wasn't supposed to hit and sparks were flying.

2) The other issue the tractor is having is that it runs OK in 1st gear, but anytime you throw it into a faster gear it will choke out and stall. We are going to take the carburetor out and clean it out. Would this help? Might it be another problem?

I can't imagine much is wrong with the tractor, it was only used to cut grass, and stayed in a shed 100% of its 24 year old life.

Any help or hints would be great!!!!