Technical Stalling

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Technical Stalling

Cschaedler

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Hi. I have a 72 Lusso that I bought a few weeks ago for my wife. Already enjoying issues. Motor was rebuilt last year and starts easily and seems to idle well. Issue is when you slow to a stop it stalls 90% of the time. I have adjusted both the idle and the mixture without success. Thoughts are appreciated!
 
Probably just something has gone a bit out of tune. I would check the points gap and tappet clearances.
 
when you slow to a stop it stalls 90% of the time.
Does the temperature gauge rise when the car idles? If so, that may be down to an air leak - air drawn in from somewhere which makes the mixture too weak.

Strange to say.. but an over-rich mixture can cause similar problems. If the car is difficult to start when hot, it may be an over-rich mixture.

Have a look at your plugs - they may give an indication. I've attached an image which may help:
 

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Does the temperature gauge rise when the car idles? If so, that may be down to an air leak - air drawn in from somewhere which makes the mixture too weak.

Strange to say.. but an over-rich mixture can cause similar problems. If the car is difficult to start when hot, it may be an over-rich mixture.

Have a look at your plugs - they may give an indication. I've attached an image which may help:
Hi Glen
The thread is in air cooled 500 classic section so I am not sure they have temperature gauges fitted.
The plug firing end picture looks to me as if someone has swapped the lean and optimum plugs round.
Not having a dig that's just how it looks to me.
cheers Jack
 
Carburetor may be flooded due to: float not adjusted correctly, float is filling up with gas because of pin holes in it, or float shut off worn.
Also check to make sure carburetor attachment nuts are tight and not loose, and that the fuel enrichment ("choke") is completely off.

Where in the USA are you?

John
 
Thanks for the response on the float. I am beginning to suspect same. I hope to have time to take a look this weekend. I am in Essex, CT.
 
When you have the carb off to check the float, check that (a) the base of the carb is flat and, (b) the bakelite spacer is flat on both surfaces. Any warping of these surfaces can lead to stalling as they will allow air in which will weaken the mixture. To flatten off the surfaces, tape a sheet of emery-cloth onto a sheet of (thick) glass if you don't have any other absolutely flat surface. It will a bit slow and tedious, but is necessary. If the engine is starting OK, both hot and cold and actually idling Ok, I would expect the float to be OK, but it is well worth checking---even a small amount of fuel in the float will affect engine running (any fuel in the float will 'rattle' as you shake it). Check that the needle-valve has a smooth taper on the 'needle' (and a little ally washer under it).
Are you actually in the town of Essex, or in Essex County? I have a good friend in Uncasville--probably coming over in 2019 to see him and his wife. Keep in contact---feel free to contact me direct if you wish to.
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So I sprayed some cleaner into the carb as a first attempt, and it worked. Have driven the car half a dozen times with no stalling. Thanks for all the other advice.

I am in the town of Essex about 25 minutes from Uncasville.
 
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