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TR4/4A Carburettor is French for DON'T TOUCH!

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R

rnpennington

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OK, I didn't follow the directions in the title and I touched them. Didn't drive the car for a while and the floats got stuck and fuel was pouring out the bottom of the carbs, ZS 175CD carbs. OK, easy fix I think, took the carbs off, opened the bottom to reset the float, changed the o-rings in the jet assembly. However, it took about three weeks for this all to happen.

Now, having taken them apart I know I have messed up the settings from before. How to I get it to a setting that will run the car and allow me to adjust it properly? At this point, it will not run, only start with starting fluid.

First question, what I have marked as Part 1. Is this screwed in all the way to the top or some other position?
Second, once part one is fixed properly, do I screw part 2 in all the qway and back off a certain number of turns or what?

Thanks for the help!
 

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Screw the big one all the way until it is tight, but not king kong tight. Make sure you have a GOOD O-ring in that groove.
The small one is the actual jet adjustment 'screw'
The best way to set the jet is to remove the top of the carb, the spring, then the air valve with the 'rubber' diaphragm attached so you can see (and measure) the jet... then using the adjustment screw turn it until the HOLE in the jet is about 1/10 of an inch below the surface of the bridge...that's the baseline setting.
I hope I'm safe in assuming you know how the air valve and diaphragm fit back in their proper place
In the future for fine tuning when viewed from ABOVE Counterclockwise rotation of the adjustment screw raises the jet, which leans the mixture
ZS CARB ADJ JET 001.JPG

ZS carb bridge and jet 001.JPG
 
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There's plenty of information on-line and in the shop manual about adjusting carburetors. Also, in the archives here. I think you should start by educating yourself on the way Strombergs operate--much the same as SUs, and probably there is more info on them, so any info on SU info you find is mostly relevant, too. They're actually pretty simple.

The only tricky adjustment, in my experience, is the mixture. I find it easier on SUs, as the effect of lifting the damper is more pronounced. But, with a little care and experimentation, you should get good results.
 
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