Starting Problem

["paulus260572" <paulus29@xxxx>]

Hello all,

The problem I'm having on starting is this sometimes when I crank the 
car over its like the battery is flat and there's hardly any reading 
on the volt gauge then all of a sudden the car will start and be fine.
I just put new starter motor on and when I test the battery with a 
meter on tick over its about 13.7 volts and rises when you accelerate.
Any ideas?
P.s.I have a delco alternator but don't know what model?

Cheers Paul.