Small Engines (Lawn Mowers, etc.): Briggs intek starting, cold cranking amps, jumper cables

Question
Briggs #311777 0148-el 996209zd 17 h/p. New battery, have taken starter to shop and he only found one worn bushing, have adjusted valves, replaced oil. With spark plug out engine will spin pretty well, while spinning put your finger in plug hole and engine drags down, same result with larger battery connected to starter by jumper cables.The starter shop applied load after full rpm was reached.What do you suggest?

Answer
I have had bad battery cables generate too much resistance leading to an increase in voltage drop.  I've also found solenoid exciter circuits with the same problem.

Have you dis-connected the battery cables and cleaned the battery cable ends and battery terminal posts with a wirebrush?  Fixed a lot of starting problems just by cleaning the connections.

How many Cold Cranking Amps  (CCA) is the battery?  I've seen cheap batteries not have enough power to rotate the engine.

See the link below for testing the voltage drop:
http://www.aa1car.com/library/voltage_drop_testing.htm

Let me know if this helps.
Eric