Hard cold start.
 

On starting my Volvo 740 from cold the engine splutters and coughs and idles so poorly and unevenly it's just ready to cut out even though the choke flap is closed, auto choke. I give it a little throttle to stop it from cutting out. After a couple of minutes the engine settles into a very nice even idle at 800 RPM and the choke flap is fully opened at that stage. The spark plugs were black and sutty but dry when removed. I removed also the silver pipework going to the air intake from the exhaust and applied heat from a heat gun. Sure enough the flap inside moved slowly backwards with the heat to close off the heat supply. By the way, the engine is the B230K, carburettor fed engine. Any advice or help would be greatly appreciated.

You’d be better served posting this in the dedicated 700 series section. Good luck.

In addition to asking in the proper place, wait until the petrol level in the tank is at 1/4 or below and then add :

https://www.toolstation.com/methylated-spirit/p99550

Add all of it, it sounds suspiciously like condensation in the tank. Have a read of this thread, you'll see what i mean :

https://www.volvoforums.org.uk/showt...87#post2686587

It could of course be that horrible Pierbug carb playing up but try the meths first, it's cheaper! :thumbs_up: