NOTE: Cranking a engine over that won't start via an electric starter until the battery goes dead is a excellent way to burn up an expensive starter! If the engine won't start... stop cranking and do some trouble shooting.
1 - Remove the spark plugs. What do they look like?
2 - Take a compression reading. What are the psi readings?
3 - On that 1974 model, rig a spark tester to have a 1/4" gap for the spark to jump. The spark should jump that gap with a strong blue lightning like flame... a real SNAP! Does it? Note that the gap is important. Checking spark any other way is a waste of time.
If the two above areas check out as they should, that leaves the fuel section which is usually a clogged carburetor... not always but usually!
Let us know what you find.
