Carb tune on a 74 1256 HC

[wyke]

Finally got it running with new valve springs and head gasket.

However , it takes a lomg time to turn over before it starts.

Choke seems to make little difference.

I have turned out main jet by about one and a half to two turns.

I feel sure all the electrics are fine now and when warm it ticks over nicely and drives ok.

Just the starting and initial running that the choke seems to have no control of-

any ideas welcome
thanks

[griffonmark]

I replaced my fuel pump and cured the same problem.

[Sweden]

I have the same issue on my 75 (But with an older engine with the Zenith 301Z carb) I have a heater installed and with that on or inside 5hrs from driving it starts right away, but when it has been standing for a long time it takes quite a while before it starts. I have the same kind of symptons like you wyke, and the petrolpump is brand new, along with everything that sparks and service to the carb.

Have you come up with a solution?

Rgrds
Christer

[griffonmark]

Hi Christer

I assume by heater you mean a carb heater? If this works and the car starts when warm it suggests you have a cold start problem, perhaps too weak a mixture. I presume you have checked the choke operation. If the choke is OK check for air leaks at the manifold or in vacuum pipes as these can weaken the mixture.

Regards

Mark

[Sweden]

Griffonmark,

No it's not a carb heater. It is used to warm up the engine during wintertime. This winter has been warm so far, but typically a Swedish winter can mean down to -20 degrees. Brrrrrr!!! That means problems also for new cars so you will need one of the following....

http://wup.defa.com/en/wup_products_preheaters.html

However.. I will check the vacuum pipes. At present they are not tightend in any way so that might be the issue for me.

Rgrds
Christer