Carbs

[BJ1]

You can get fuel cut off idle jets for ICTs - they were made for ICH carbs which are ICTs fitted with a choke. Try the Land Rover folks because they use them in place of the stock carbs. Eurocarb may have some. Try here http://www.dellorto.co.uk/merchandi...tNo=43927.00001&CategoryID=3&PartsectionID=61
But your engine is indeed running rich so check needle valves, fuel pressure and main jet sizes. Don't worry too much about carbon in the heads. When you get the mixture right it will burn off after a good run at around 3500 rpm. I certainly would not pull the heads off just because it has been running rich for a while.

 

[mattd1984]

Regarding main jet sizes, do larger or small make it run less rich?

 

[Trikky2]

Smaller main jet will make it weaker but dont just mess with it if you dont know what your doing since running too lean can cause overheating and catastrophic engine failure.

Before messing with jets, the first thing I would try is check the idle mixture settings, adjusted with the idle mixture screws, since at light throttle this has a lot of effect and you may find that setting the idle mixture correctly will cure the problem.

If your not sure then get some help.

 

[mattd1984]

I haven't touched the carbs since they were setup buy a specialist on the rolling road 2 years ago. Maybe he set them too rich then?

 

[mattd1984]

So today i took one off my carbs of and found the following jet info;

Idle jet 55
Emulsion tube F78
Bottom of float chamber sitting at angle (Main) 35 which think must mean 135
Bottom of float chamber 40 (not sure what this one is)
Air 160

 

[fire3500]

Your jets don't seem absurdly small or big Matt, more on the small-to-just-right end of things and given that standard EMPI carb kit ships with 52 idles and 130 mains it sounds like your engine tuner has jetted it.

Start mechanically, check compression and set valve clearances to spec (your engine spec, not a Bentley... you might have non-standard rockers etc.) then your points (ignore if on electronic ignition) and then ignition timing. If that doesn't sort it then consider getting whoever rolling road set it previously to check it out and set it up again for you. If that doesn't sort it then you need to address the fact that when you kill the spark there is sufficient heat to cause dieseling. At that point I'd be considering getting the heads off for a look-see.

Good luck, keep us updated!