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Tuning
electricmonk - November 20th, 2007 at 10:04 AM

I have a 72 Square, its had the motor enlarged to 1700 and a bigger cam somewhere around 15 years ago. It's manual and running 32pdsit's. Points replaced with Pertronix (sp) unit
Plugs set at .6mm gap
Timing is at 5 degrees as 7.5 makes it ping going up hill
Carbs are stock jetting as listed by VW specs.
Fuel discharge is roughly .5cc
Fuel height in the bowl is 16mm below the top.
Floats are 7.3 grams but originally had 7 gram ones in there (Not the first late carb I have seen with this)
I have two fuel filters. One before and one after the fuel pump. The one after the pump seems to be a lot less than half full when idling.
However I am using heaps of fuel and occasionally when in third or fourth gear seems to lurch a bit like its starving for fuel.
The idle sounds a little iffy to me. Not missing heaps but the note seems wrong. Sort of flatter than it should be.
I have rebuilt these carbs a few times now and it ran better with a miss match of parts than it does stock. I thought I found the problem the other day when #1 plug was found to have almost stripped out. But after it was repaired the was no change to the idle or fuel consumption
Is there any reason why it would have these symptoms?


electricmonk - November 20th, 2007 at 07:46 PM

Air correction jets were
150 for the left and 120 for the right as per stock. Changed these before leaving work to 140 on both. No real change to the idle note. Fuel consumption may be a little better. When I fist started out from work it backfired twice through the exhaust but after a few minutes settled down. I have noticed when adjusting the idle screw that the motor vibrates a bit when it's correct. I can also "hear/feel" a cyclic vibration when I pull up at the lights
And just to be more quirky she still goes up reasonably steep hills like a rocket. I can start at 40 mph at the bottom and be resisting the urge to go over 60 by the top.