MG Car Repair: starter problem midget 1500, voltage drop test, starter problem

Question
Hi, I recently bought a midget 1500 for restauration. Bodywork is sound but I found a 88ah battery built in with which the engine starts and runs fine. When I replace it with a smaller battery (36 or 44ah) the starter is not turning. I checked the cables and put the 88ah battery back, runs fine... I replaced the starter, same problem. I went direct from plus to the starte by a 4mm2 cable, no result, the engine is not turning. I can push the car in the 4th gear without problems and now I am running out of ideas. Any advice? Many thanks, Frank

Answer
Hi Frank,
Unless the compression has been jacked up extremely high the lower amp hour batteries should have worked.
You need to do a voltage drop test on the power cable and the grounds to see what is wrong. Also do a voltage test on the battery and see what the voltage drops to when the starter is used. Let me know the results and readings.
Howard