Technical Acceleration Issue

[John Nolan]

Good Evening!
My 1972 Fiat 500 R has thrown a peculiar problem. I was recently driving home from work and after getting off the exit and coming to a stop the 500 bogged down and would not accelerate while idling just fine. In the following week I had checked points, timing, cleaned the carburetor (float is good and jets appeared clean). Of note, the spark plugs appear black with soot after each attempt (see picture). This seems to allude towards the mixture being too rich but as stated before the carburetor and float within seem correct and damage free. Pictures and video is attached. Thank you for any and all help.

Recently replaced distributor, condenser, coil, but weeks prior to this dilemma.

 

[bugsymike]

Good Evening!
My 1972 Fiat 500 R has thrown a peculiar problem. I was recently driving home from work and after getting off the exit and coming to a stop the 500 bogged down and would not accelerate while idling just fine. In the following week I had checked points, timing, cleaned the carburetor (float is good and jets appeared clean). Of note, the spark plugs appear black with soot after each attempt (see picture). This seems to allude towards the mixture being too rich but as stated before the carburetor and float within seem correct and damage free. Pictures and video is attached. Thank you for any and all help.

Recently replaced distributor, condenser, coil, but weeks prior to this dilemma.

Dirt under the needle jet for the float?
We used to test needle jets by blowing into them and turning the carb upside down to check it shut of fully.
Best to use a clean bit of plastic hose unless you want to test fuel for the rest of the day.

 

[the hobbler]

Good Evening!
My 1972 Fiat 500 R has thrown a peculiar problem. I was recently driving home from work and after getting off the exit and coming to a stop the 500 bogged down and would not accelerate while idling just fine. In the following week I had checked points, timing, cleaned the carburetor (float is good and jets appeared clean). Of note, the spark plugs appear black with soot after each attempt (see picture). This seems to allude towards the mixture being too rich but as stated before the carburetor and float within seem correct and damage free. Pictures and video is attached. Thank you for any and all help.

Recently replaced distributor, condenser, coil, but weeks prior to this dilemma.

Check that the "fuel-enrichment" (often, incorrectly, called the choke) is coming off when you depress the choke lever between the seats. Also--PLEASE remove that filter by the fuel-pump--not only is it is not required, but should it leak, it will spill fuel over the dynamo, which is by all accounts, a good way to start a fire! You have already got 3 filters in the system---tank-unit, top of fuel-pump and top of carburettor. I would also suggest that you obtain, and fit, a pair of the rubber collars that go round the spark-plug extenders (they will stop some of the 'cooling' air being lost around the plugs) and clip the plug-leads into the little holders---1 on the top of the thermostat-housing and the other on the rocker-cover---that is what those little round grommets are for.

 

[bugsymike]

Only just listened to the video, to me it sounds like it may be ignition breaking down, is the rotor arm/distributror cap and HT leads in good order, not tracking or HT leads breaking down under load?
Are both spark plugs equally sooty?
Also does it run clean with new spark plugs and then deteriorate as it get rich indicating a carb issue, also if running rich the exhaust smell should be a guide.
By the way if carb flooding you can sometimes physically see it by looking down the carb with engine idling, I realise not a lot of access, maybe a mirror?
By the way are the new "Recently replaced distributor, condenser, coil, but weeks prior to this dilemma." of good quality?

 

[the hobbler]

Only just listened to the video, to me it sounds like it may be ignition breaking down, is the rotor arm/distributror cap and HT leads in good order, not tracking or HT leads breaking down under load?
Are both spark plugs equally sooty?
Also does it run clean with new spark plugs and then deteriorate as it get rich indicating a carb issue, also if running rich the exhaust smell should be a guide.
By the way if carb flooding you can sometimes physically see it by looking down the carb with engine idling, I realise not a lot of access, maybe a mirror?
By the way are the new "Recently replaced distributor, condenser, coil, but weeks prior to this dilemma." of good quality?

Check the float, especially if it is an original 'soldered brass' float. The ethanol in modern fuel will attack the solder, which will allow petrol to leak into the float---the float will sink lower and lower, and therefore not shut off the needle-valve correctly, which will lead to a very rich mixture. If the float 'rattles', it has petrol in it---they cannot be repaired, but a new one is not very expensive. If you do have to replace the float, do not forget to check the float setting/adjustment when you fit it .