starting problems

hi  i have a 1983 tintop golf with 1.8 8v engine out of a scrcioco in it. the cars was 1.1 c.

now the problem is that cars srtarts fine most the time but sometimes when its it just won't start. I've checke the battery with a guage and its fine. if charge the battery the cars seems to start fine for a few weeks but them starts palying up again.

i fitted a new battery in may but maybe it the wrong size what code battery do need for the 1.8.

also could it be the starter motor?

i've also change the leads and coil

Is this injected ?

it could be sooo many things! if you've got a good battery with a 'i'm working light' then it's not your battery or alternator.
list of things you need to check.

wiring from battery to everything, from ignition to starter
starter motor
injectors, make sure they're not worn and useless (2 of mine were knackered, have second hand ones for the moment but needs new ones soon)
dizzy/ spark plugs seeing as you've already changed the leads
the ignition itself might be gone (mines just died)
fuel pump
fuses

depending on when you've last changed the above mentioned will rule them out. check the least expensive and least labour intesive things first. if it's them you've not wasted  much time.

mine died the other week after about a year's worth of playing up, i was having to pump the fuel into get her to fire up. then it was pump turn off pump and off she'd go.. then it was continual pumping for aaaages then she'd go.
recently turning the key hasn't elicited any response from anything, no noises whatsoever. turn off and start again pump and away!
in the end it turns out the ignition has lost it's 'stops' and turns too far back to 'off'.

if it's anything like that and the only thing you've not checks is fuel pump and ignition, i'd suggest changing the whole ignition (slightly easier than changing its component parts at a guess, no drilling involved) it's not expensive or hard (although i've yet to figure out how to get the housing off mine despite 2 haynes manuals, which don't actually tell you how to do this, might want to see my ignition housing thread i'm about to post!)

hope this helps

Does the car have the following parts:

5th injector
thermo time switch?