car dies

tigermoth · December 2007

my '35 6 cyl 212 cu. in. car idles great. you can set the idle slow enough that you can almost count the fan blades. runs smooth whether engine is hot or cold. when driving at cruising speed and push in the clutch, the engine dies. when i let out the clutch she starts right back up. runs smooth. if i approach a stop and instead of pushing the clutch in at cruise speed i apply brake and as a result the engine RPM is lower when i push in the clutch she does not die. (i am not saying this is clutch related, it obviously it is not, but i am describing the symptoms) so my question is, what would cause an engne to die when it goes from high RPM to off the accelerator? when the RPM comes down slowly (i.e. i brake to a slower speed before pushing the clutch in) she runs fine and does not die. because of that i do not believe it is vapor lock...plus she starts and runs smoothly when the cluctch is let out or if i don't notice she has died she starts right back up on the starter. i have set the idle to a higher RPM and that helps but the idle speed it takes to make a difference (1000 to 1200 RPM) seems too high and is that the REAL cause....too low an idle speed??? any thoughts? thanks. regards, tom

hudsonsplasher1 · December 2007

tigermoth wrote:

my '35 6 cyl 212 cu. in. car idles great. you can set the idle slow enough that you can almost count the fan blades. runs smooth whether engine is hot or cold. when driving at cruising speed and push in the clutch, the engine dies. when i let out the clutch she starts right back up. runs smooth. if i approach a stop and instead of pushing the clutch in at cruise speed i apply brake and as a result the engine RPM is lower when i push in the clutch she does not die. (i am not saying this is clutch related, it obviously it is not, but i am describing the symptoms) so my question is, what would cause an engne to die when it goes from high RPM to off the accelerator? when the RPM comes down slowly (i.e. i brake to a slower speed before pushing the clutch in) she runs fine and does not die. because of that i do not believe it is vapor lock...plus she starts and runs smoothly when the cluctch is let out or if i don't notice she has died she starts right back up on the starter. i have set the idle to a higher RPM and that helps but the idle speed it takes to make a difference (1000 to 1200 RPM) seems too high and is that the REAL cause....too low an idle speed??? any thoughts? thanks. regards, tom

Tom;

Check to make sure your idle adjustment is correct. If it's too lean, it will stall when you come to a stop. Rule of thumb, is one half to one and a half turns open from closed. If you have a manual, check to see what the adjustment is. Or just try opening it a half turn at a time until the problem gos away.

Gene.

Unknown · December 2007

Check to make sure your clutch linkage doesn't have some electrical wires hanging in the way of travel and shorting out, also did this car have a vacuum clutch at one time? If so, perhaps when the clutch is operated it opens a vacuum valve somewhere and causes the engine to lean out and die...... just a thought but possible.

Jon B · December 2007

Does the 1935 carb have a dashpot? If so, is it operating correctly, or might it need a new seal?

"Dashpots were used to prevent stalling when the gas pedal is suddenly released when braking (on automatic transmission cars), to improve shifting on manual transmission vehicles, and, in later models, to control emissions. When the throttle is closed quickly, the mixture can become too rich because of the high vacuum under the throttle plate. In this case, the dashpot served to slow the closing of the throttle plate, decreasing emissions" [courtesy of The Carburetor Doctor]

If the dashpot piston seal isn't good, it moves too rapidly, and the car will stall under the circumstances you describe.

Unknown · December 2007

tigermoth wrote:

my '35 6 cyl 212 cu. in. car idles great. you can set the idle slow enough that you can almost count the fan blades. runs smooth whether engine is hot or cold. when driving at cruising speed and push in the clutch, the engine dies. when i let out the clutch she starts right back up. runs smooth. if i approach a stop and instead of pushing the clutch in at cruise speed i apply brake and as a result the engine RPM is lower when i push in the clutch she does not die. (i am not saying this is clutch related, it obviously it is not, but i am describing the symptoms) so my question is, what would cause an engne to die when it goes from high RPM to off the accelerator? when the RPM comes down slowly (i.e. i brake to a slower speed before pushing the clutch in) she runs fine and does not die. because of that i do not believe it is vapor lock...plus she starts and runs smoothly when the cluctch is let out or if i don't notice she has died she starts right back up on the starter. i have set the idle to a higher RPM and that helps but the idle speed it takes to make a difference (1000 to 1200 RPM) seems too high and is that the REAL cause....too low an idle speed??? any thoughts? thanks. regards, tom

Yes, idle speed too low!:)

SuperDave · December 2007

Check the float level. Modern (improved??) fuels can act differently and cause some momentary flooding. The fuel blending changes at different time of the year dpending on where you are located.

tigermoth · July 2008

thanks to all. i thought i would write again to tell you my progress. after reading all of the posts it appears at least part of the problem was idle mixture. i thought i would open the carb up to check the float level and i found it was exactly 3/8" from the tip on casting lip to the seam on the float. this is what the overhaul manual for the 454S carter WA-1 carb calls for. do modern fuels require an adjustment to the 1930's setting? thanks again. regards, tom

Unknown · July 2008

tigermoth wrote:

thanks to all. i thought i would write again to tell you my progress. after reading all of the posts it appears at least part of the problem was idle mixture. i thought i would open the carb up to check the float level and i found it was exactly 3/8" from the tip on casting lip to the seam on the float. this is what the overhaul manual for the 454S carter WA-1 carb calls for. do modern fuels require an adjustment to the 1930's setting? thanks again. regards, tom

Was wondering about plug gap also with fuel now and fuel back in 1929 ? 1929 manual calls for .028 plug gap. Thanks, Ron

Uncle Josh · July 2008

Geoff Clark says you have to lower the float 1/8 inch for the new fuels

Geoff · July 2008

It would also pay to do a thorough check of all the adjustments, including the anti-percolator valve setting. If this doens not open and shut correctly when the linkage is back, it will affect idling mixture.

Geoff.

car dies

Comments

Categories

In this Discussion