Starting Problems

I have a 91 VW Golf GL 5 speed. Every once in a while it will not start. I replaced the altenator and battery. Now I am trying to replace the thermostat *(but can find it under the hood)* The Battery cables get very hot to the touch. If I pop the clutch enough it will start but it stalls out in 1st or 2nd gear. Thinking it could be starter but not sure......PLEASE HELP!!!!

I would first check the cables from the battery to the chassis/engine ground & starter solenoid for corrosion or loose connection. After that I would have the starter checked for drawing too much amperage.