Technical Engine not running smoothly

[FR85]

I would suggest disconnecting the battery if possible when doing anything with fuel on these cars, everything can be live even with the key off.
If it was a problem with the starting device I dont think it would cause a normal running problem.
I have had a quick skim through all the posts, have you confirmed if you have spark? Remove a spark plug and earth it to the engine hoist or any decent metal on the engine tomorrow evening when it's getting dark, with the ignition on have someone pull the start lever and see if you can see lightning.
If you are on your own and this is a last case out of desperation and at your wits end scenario, pull out the plugs to eliminate compression, with the ignition on spin the engine by hand and it will generate spark, lighty holding a plug in your other hand it will give you a little jolt......not recommended if you have a heart condition which I suspect you may be close to with the frustration this must be causing, even a slow full turn will windmill a spark. Other way would be to remove the cap and with the ignition on and the points closed, open and close them with an insulated screwdriver, this too should induce a spark and it will be audible.
If you have spark, pull the main fuel feed off the carb, pop the carb end iof the pipe into a coke bottle and with the ignition off and again with your trusty assistant, after a couple of turns make sure its pumping fuel, again if you are solo a couple of turns by hand will eventually result with fuel in the bottle if the pump is working as the pump is a mechanical pushed design.
If you have spark and fuel and you are breathing then you have all the ingredients for the car to run and then, its something like the carb or possibly timing.

I had as mentioned very similar to you recently, I was fully convinced it was fuelling but it turned out to be an electronic ignition and after doing a full carb rebuild I was kicking myself. Car would barely run, zero power, when I accelerated it would die, would just about idle ect.....
Based on that experience I still think its ignition, perhaps burned out points. The introduction of heat and hard starts and problems when warm all lead me to ignition.

 

[jezashton]

I have an update on this, but unfortunately, still haven't resolved the issue!

Working on the theory that the issue was rust particles from the fuel tank clogging up the carb, I've done the following:

• replaced the fuel tank
• replaced the fuel pump
• dismantled, cleaned and reassembled the carb
• flushed the fuel to ensure it and the pipework are rust free

Feeling pretty hopefully I put it all back together and the engine started fine (which was a relief!) but still the same problem - unable to rev the engine without it cutting out.

My next plan is to think about ignition. I've already replaced the condenser with the Swiftune version so thinking of doing the following:

• New spark plugs
• New HT leads
• New ignition coil - any advice on which to purchase, there seem to be a few options

I need some advice on the distributor - it's way past my ability to start messing with points, timing, etc. Do you think I should do all the above first and see if that sorts it?

 

[Goldnrust]

If you were able to dismantle, clean and reassemble a carb, there’s no reason you can’t do some basic checks on the distributor before you have to dip into your pocket for parts you may or may or need.

Do you have a multimeter? If not, it might be a wise purchase. You can use it to check the resistance across the windings in the coil and of the spark plug leads, which can help you assess if they are in good condition.

I would suggest starting with checking the points gap. Take the distributer cap off, and then the engine over by hand till you see the points are open at their widest. Then use a feeler gauge to measure this gap. You are looking for 0.5mm. You may also wish to look for signs of corrosion on the points and potentially sand / clean them.

After that checking the static timing would be my next suggestion.

If you search the forums you will find setting the points and checking the timing has been covered many times and honestly is considerably less complex than a carb rebuild!

 

[the hobbler]

If you were able to dismantle, clean and reassemble a carb, there’s no reason you can’t do some basic checks on the distributor before you have to dip into your pocket for parts you may or may or need.

Do you have a multimeter? If not, it might be a wise purchase. You can use it to check the resistance across the windings in the coil and of the spark plug leads, which can help you assess if they are in good condition.

I would suggest starting with checking the points gap. Take the distributer cap off, and then the engine over by hand till you see the points are open at their widest. Then use a feeler gauge to measure this gap. You are looking for 0.5mm. You may also wish to look for signs of corrosion on the points and potentially sand / clean them
After that checking the static timing would be my next suggestion.

If you search the forums you will find setting the points and checking the timing has been covered many times and honestly is considerably less complex than a carb rebuild!

Just for interest---who was the "Fiat 500 specialist" that fitted your engine? I know that it was an engine that you supplied to him, but surely he should have given the car back with the engine running correctly---I would have, and yes, I was in the motor-trade for many years and would have been very embarrassed if I handed back a car with the engine not running correctly, no matter WHO supplied the engine. Have you had a word with the "500 expert"?

 

[ronstox]

I noticed in the photos that the thermostat "door" is open. Was the engine hot or cold when you took the photos? If it was cold, then I suspect your thermostat bellows need replacing as well. Just something else to add to your to-do list.