Full disclosure - I'm not in the forklift business, I'm just trying to help my wife's family get this thing going so they can sell it as running machine. I searched all over the 'net and this forum is among the very few potential resources I could find. Any help would be greatly appreciated and thanks in advance for any help offered.

My father-in-law passed away and he had a Cat T40B. I know it ran well right after he got sick as I was the last person to use it, but then it sat for about a year completely untouched. I've cleaned the carb and got it running from a gas can, then cleaned the tank and lines, as well as replaced the filters, and now have it kinda running (see below - idle issues) from the tank but I have a few questions:

1. There is a valve on the driver's left lower side that has two feeds (or a feed and return) from the fuel tank and the center feeds the fuel to the engine. The **** is missing, but I've managed to determine that in one position it connects the port on the side of the tank to the engine feed and with a quarter-turn, it connects the port on the top of the tank to the engine feed. But what exactly is it and what is its purpose?

2. When I cleaned the (Holley single barrel) carb, I didn't touch the external idle set/stop screw that impinges on the choke arm, but now, the engine won't idle unless you slightly depress the throttle and the idle set/stop screw shy of the choke arm about 1/8" or so. I don't want to adjust it without at least trying to get some info. Unfortunately, I forgot to note its position prior to the carb removal and cleaning, but I know for a fact that it ran well prior to sitting and I also know it was untouched for the year it sat up. Can anyone provide any pointers or if it isn't asking too much, anything from a manual to help set up the linkage and carb (even a parts diagram would help at this point).

Thanks again in advance for any help, guidance or information.