Hello, I have an issue with the idle on my carb 308 1979. When I’m at cruising speed and have to slow down for a stop light the idle first goes down to the usual 900 rpms but after a short while it slowly drops gradually down to 500 rpms and the engine almost cuts out. It only happens when slowing to a stop from speeds above 50 km/h it seems. Under normal driving around the idle sits steady at 900. I have a Pertronix, new plugs, cables and synched carbs. I can’t for the life of me figure out what is happening. Any ideas?
There are a few possibilities for this. More info would be nice, first of all when did it start happening, after some adjustments? Does the temp gauge rise up when this happens? Coming from 50 to a stop the temp may be getting too high, also could be a sticking device inside carb, were they rebuilt very recently? Does the engine stumble or ping when this occurs? if you don't touch the gas does it recover by itself?
Possible loss of fuel due to vapor lock from the engine heat. Is it worse on hot days and better on cool days? Have you checked your fuel pressure at the carbs? Brian Brown San Francisco Motorsports
I had the same problem on a 1954 Cris Craft ML flathead 6. A little different, I know. Problem was a float lever set too low. It might relate? Image Unavailable, Please Login
