carb question

[kever65]

Hello,

i already asked this question before, but i put it the wrong way, i will try again, the problem with my 1776cc 48IDA engine is when i do a cold start my air fuel ratio is around 17 18 witch is normal since the engine is cold, when i play a little with the accelerator it keeps on running and after a minute or so it keeps idling by itself with a air fuel ratio around 13, so, far everything is normal. when the oil temps starts to go up lets say 30 degrees it idles at 12.4 Afr, where it should with this cam and Small displacemen,t but then when the oil is between 50 an 70 degrees something strange happens, its starts leaning himself out 17,18 Afr, when the engine is reaching 80 degrees and more,(normal driving conditions), everything is normal again. for street use this is not a issue since he doesn't stay long at this temperature but on the strip it is the temperature where i do a lot of my runs, and i have to keep playing with the accelerator to keep the engine from stalling when i am doing a burn and go to stage the car. I can solve the problem by turning the mixture screws a little but when the engine gets hot and idles it then starts fouling the plugs. i already checked my valve play at this temperature and everything was fine, carbs where also still in sync.

what can cause this !!??

thanks in advance

[nicolas]

any news or progress? i have been thinking about it, but can't really comment or pin down on what's happening. but i hope you are able to find out what is wrong.

[spanners]

Hi, odd that one , if it runs a bellcrank system it might be linkage related with engine expansion,  but not with a crossbar type , any temperature indexed ignition control or modules on it?

[Martin S.]

Check for a vacuum leak at the manifolds. If mixtures change with engine temps, something is opening and closing and letting air in thus leaning it out at certain conditions.