Tweeker521 Posted October 24, 2012 Report Share Posted October 24, 2012 I got a 1971 Datsun pick up, it turns off on me when I come to a stop. Idk why, I already cleaned it out and replaced the fuel filter, spark plugs, did the timming. Dose any body else have this problem? Quote Link to comment
datzenmike Posted October 24, 2012 Report Share Posted October 24, 2012 Confirm that the valve lash is correct and there are no loose or overly tight valves.... Check that the ignition timing is 12 degrees BTDC... Now... Get it running and warmed up, and adjust the idle mixture screw in and out looking for the fastest smooth position. This is done by turning the screw in until the idle becomes rough from being too lean. Then turn the screw out until the idle becomes rough from being too rich. Now just pick a spot half way between. Likely the idle speed has increased, so turn the idle speed screw out to lower it. Repeat the in and out adjustment looking for the fastest smooth idle until you can't improve it. Set the idle speed to 750 or so. Quote Link to comment
Tweeker521 Posted November 1, 2012 Author Report Share Posted November 1, 2012 Confirm that the valve lash is correct and there are no loose or overly tight valves.... Check that the ignition timing is 12 degrees BTDC... Now... Get it running and warmed up, and adjust the idle mixture screw in and out looking for the fastest smooth position. This is done by turning the screw in until the idle becomes rough from being too lean. Then turn the screw out until the idle becomes rough from being too rich. Now just pick a spot half way between. Likely the idle speed has increased, so turn the idle speed screw out to lower it. Repeat the in and out adjustment looking for the fastest smooth idle until you can't improve it. Set the idle speed to 750 or so. Thanks for the heads up, I'm gonna do this ^^^ as soon as I put the carb back in the truck, I'm gonna rebuild it, and put a new fuel pump in too. Quote Link to comment
68Datsun510 Posted November 1, 2012 Report Share Posted November 1, 2012 I dream of a 750rpm idle lol, my engines happy spot is 1250rpm... Cams... Quote Link to comment
ggzilla Posted November 1, 2012 Report Share Posted November 1, 2012 The most common problem of dying when coming to a stop is a vacuum leak. So check for that FIRST before you set the idle-mixture. Otherwise you mask the problem. Leaking intake gaskets and carb gaskets are NOT the most common problems. More often these are the causes: * broken/cracked hose ends * leaking vacuum motors (diaphragms, ESPECIALLY the distributor) Any of these should be tested: * Distributor advance can & hose * Choke pull-off & Hose * Air Cleaner heat-flap Motor & hose * Throttle Opener & hose * Any other small vacuum hoses Hoses crack right at the ends usually so inspect carefully. To test the vacuum diaphragms, use the finger test or a vacuum gun. Quote Link to comment
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