Is this as fast as it will go .?.!.?.!..

[Threewheelmotion]

Hey guys, just got a new to me 1990 Club Car DS. I have fixed a few corroded wires, changed he front bearings and hub and checked all the batteries for voltage. I’m not sure how old the batteries are but I’m pretty sure they are on their way out. When charged they read approximately 7.3 each. I have not done much riding yet because I want to drain the rear fluid and replace because it hasn’t been changed in a very long time. This is the question ??? Shouldn’t this thing run a little faster than 12 mph ? I will attach a pic of it. I assume if the batteries are going bad it should still run at full speed for at least a little while. What could be causing it to only go 12 mph ? Thanks !!!