Carb Trouble.....as always!!

[Billy Smalls]

Hi
I am determined to get my 144 running as sweet as it can.

The compression, valve clearance, timing and distributor are as good as they are ever going to get – new head, valves and springs; valve clearance set correctly; 123ignition / timing all installed and set up.

So, now onto the carb. It’s a 175CDS with the yellowed temperature compensation thingy which I have set up as per the article in the recent Driver mag. It starts to open at 30 degrees and fully open at 60 degrees. There’s a new diaphragm in there, the right amount of ATF in the dashpot. It has the fixed jet – that is to say it’s the simple bolt in the base with no provision for adjustment there.

The engine idles well and once it’s up to 40mph it goes along nicely but getting there it struggles a bit – at least more than it should I feel.

When I brake into a junction it sometimes falters – which makes me think there maybe an air leak to the brake servo?

Being an auto there’s a cable linkage from the accelerator to the autobox gubbins, I’ve never touched this – could this need adjusting.

The car is also overrunning at times which I switch it off at the ignition.
Hot start is still a bit of a problem though not as bad now the weather has cooled off.

There is a crack in the exhaust manifold – which I’m going to get sorted soon, thanks to classicswede.

I’d love to stick twin SUs on there but right now I’m still recovering from the ££££ of the head and 123ignition.

Any thoughts?

[140]

One or two pointers to look at: close off the servo hose with a clamp and see if that makes any difference that would eliminate an air leak from the servo. It is possible that you have an air leak from the manifold gasket try carefully spaying something WD40 along the gasket and note any engine change or possible smoke.

The needle and jet may have wear so if possible ask a garage to check the Co it should be around 2.5% at idle. Check the butterfly spindle for wear in the carb housing this may let air in.

Check the idle speed it should be around 750 – 800 rpm in park. The cable to the automatic gearbox should have a little crimp stop on the inner cable and this should have about a 1mm gap to the outer cable at idle.