starters of 1.6 and 1.8 engines are the same? difficulties in starting

Does the 1.6 and 1.8  engines share  the same starter?
I am asking because my 1988 cabby has the 1.6 EW engine but the previous owner put the 1.8 gti 8v flywheel on, as i recently discovered, when i had to change the clutch disk.
Can the 1.6 starter with the 1.8 flywheel explain the difficulty in starting every day, especially when it is cold?
If the car sits for a week, the  only way  for the car to start, is by cranking the engine with the transmission in reverse so as to move a few centimeters back and then to press the clutch pedal and fire up the engine.
The battery is fairly new and i tested for parasitic drain with negative results.

yeah you can use a starter from 1.5-1.8 manual 8v and 16v.

1.6 starter should have no problem with 1.8 flywheel, its probably just old or your battery cablign needs cleaning up