starter motor struggling to turn engine- 2.0ltr 16v bike carb conversion in my mk1.

Since I fitted a 16v 2.0ltr engine to my mk1 the starter motor has struggled to turn engine. It tries and turns over really slowely then will suddenly turn over fast for a second or so then return to slow and so on… anyway it rinses the battery before i can start the car - something is definately not right.

its been a very long project - probably over the last 4 years but i do seem to remember this problem occuring years ago and me buying a replacement starter motor - only for the problem to still exist. So i am reluctant to buy another straight away without getting some advice from people on here.. hoefully someone will turn up who's done similar conversion and had same problem?

are there uprated starter motors for sale by any chance?

cheers.. got mot this afternoon so going to have to take a spare battery down with me - not ideal! and hope i dont get stuck on their forecourt!

 

assuming its on an 020 gearbox the mk3 golf 1.8-2.0 8v starter (not TDI) is a straight fit and an upgrade.

check everything else first tho, clean up the starter, battery and alternator cables.

run a jump lead from the negative to one of the bolts holding on the starter to rule out bad earth thru the gearbox bracket

jump the red/black starter terminal with 12v straight off the battery to rule out ignition switch and wiring issues

What battery are you using? As in what model number.
Find out what the CCA (cold cranking amps) is, as it might not be up to the job. I very recently had a similar problem, and discovered that the 063 battery (which was a Bosch Silver delivering 360CCA) I had was not up to the job, so fitted a Bosch 100 (760CCA) and its faultless. The electrical engineer diagnosed that as the problem - he said that the mk1 starters are too old to be upgraded internally as nothing fits them, so the biggest battery you can fit is the best option.
The cranking ability of the bigger battery is double, and from memory it's about 40mm wider, that's all.

You can get better starter motor
I put modern type gear reduction on mine
Ok I'm in trade I paid £36 plus vat for new out right starter motor which would say turns twice as fast
Have you checked bush OK in gearbox which make starter lazy

I have got 2,0 abf fitted my mk1

just to add, Varta make the batteries for bosch so the get a Varta made ones to avoid paying the extra bosch tax I had a bosch S3 off ebay which was listed for a MK2/3 GTI rated at 360 CCA, it cranked over my ABF MK2 perfectly fine. was a little small though, I think its for the carby engines really. swapped it into our SEAT Ibiza when its battery died and got myself a bigger one. I forget what it is exactly as it was a genuine VW one nicked out of a passat in the scrappy no need to go too massive though 700odd CCA is straying into uber diesel territory which is overkill really for a petrol engine. But if thats your thing I needed to get an uber one to suit our Bora PD150, in the end I opted for a Varta E44 which can be had off ebay for £66 quid delivered, bargainous. it is a monster thou8gh so be sure to check the measurements to be sure it will fit

ive noticed with a friends abf on carbs conversion, the distributor timing plays a huge part in how easy the engine turns over.. so if dizzy timing has been messed with I would check that..

That's quite true. 
The advance on my dizzy is quite a bit as the Schrick cam is fairly aggressive, and demands that much more advance in order to run properly. This does it make it tough for a smaller battery to crank over. In fact, my cam used to turn the engine backwards slightly as the battery would try and crank it over!

Ah would explain why the poor little battery couldn't cope

mine is on stock ABF management