Starter problems

[Mcwill]

Hi guys

Been having a few starting problems, it's 1.8t golf with bat in boot.
I had a issue with the bat draining which turned out to be the stereo.
It has uprated odersy bat that I bought a few wks ago but was still struggling to turn over.
So today I fitted a second hand starter, after fitting the starter car fired up no probs :-) sorted, I thought.
Went out for 30min drive came back stopped car tryed starting no joy, just turned over really slow.
Checked bat still showing 12.5v let it cool down for 30mins.
Came back and started easy again?

Any help/thoughts would be good.

Also worth saying that the new starter had two terminals on it and the old one just had one, but still starts really good when cold.

[sparkplug]

 the battery in the back so going to be long leads & lots of volt drop , check all the battery connections are tight & very clean for a start 

[Mcwill]

Thanks for reply, going to to remove the earths tomorrow and give them a wire brush and put some copper grease on them.

[sparkplug]

or might pay you to up size the cable thickness ?

[Mcwill]

The cable looks fairly meaty. Hopefully with the earths cleaned it will spring into life.
Fingers crossed :-)

[Mcwill]

Well cleaned earths etc and still really struggling to turn over when hot.
Been doing a bit of digging on the net and I think it's to do with fact the starter I have put on has two terminals and the old one had one.
So I have ordered a second hand one from a vr6, see if this fixes it.

[Mcwill]

Hi just thought I would update this, changed the starter back to a mk3 golf abf one, single terminal point and it works fine now.
Not sure if it was down to the difference in terminals or just that the other starter was on its way out

[sparkplug]

  nice one

[Mcwill]

Well car is still starting ok but what concerns me is that when i took old starter out the end of rod on the starter was blue as if it has been getting hot.
so when i put the new one in i put some grease on it and also into the hole were the starter sits.
for the first few days the car has been really quite as in the past at has been making a constant whine from gearbox area that is in time with the revs of the engine. 
Well now the noise is back so I'm thinking its the starter sticking on?? And making the noise.
Is this possible as when you push clutch in it stops, but the gear box has just been rebult so don't think it's that.
 Could it be down to a bad ignition switch? Or not wired in correct as the car has 20v t engine and has had loads of work done to it. 
 Hope someone on here will have a clue as I'm stumped and the garage doesn't seem to sure.
Help me guys

[Mcwill]

Any thoughts, anyone?