Jerry,
It has an alternator. The truck has been converted over to a 12 volt system. The wiring diagram that I have from the wiring harness I installed a couple of years ago has the heavy red wire coming from the ignition/battery terminal going to one post on the ammeter. The other post has two wires: one is a black wire from the starter and the other is an orange wire going to the fuse block. I tried swapping the wires on the post, thinking it was a directional issue and neither way seems to matter.
That seal around the temp sensor can probably be replaced with a thick rubber O ring sized to be a snug slip fit over the temp sensing bulb as you insert it into the cylinder head. A piece of rubber fuel line tubing cut into a thin washer might also work, giving you the equivalent of a square-shouldered O ring. If your ammeter isn't indicating either charge or discharge, it might have failed internally. Are you using an original equipment generator, or do you have an alternator on the engine? If there is a wire from an alternator straight to the battery or the connector at the starter, the ammeter won't move at all- - - -it's being bypassed. There is a way to put a shunt across the back of an ammeter to avoid pegging the needle right after startup when the surge from the alternator exceeds full scale on the ammeter.
Jerry
