Technical New engine troubles - missing when rev'd up

[fiat500]

Interesting that Tony. My car came with a ballast resistor on the non-original coil. In fact it's a Lucas with a screw-in HT terminal.
Additionally, the engine had broken down because of a seriously burnt valve...connected?

 

[Vitesse]

Interesting that Tony. My car came with a ballast resistor on the non-original coil. In fact it's a Lucas with a screw-in HT terminal.
Additionally, the engine had broken down because of a seriously burnt valve...connected?

Possibly? It would certainly fit with all Marcus's symptoms.

 

[marcus550]

Great stuff! I hadn't thought of the coil not handling 13+ volts, and it is 13.4v when I measure it at the coil. And that old orange coil gets REALLY HOT. I bought a new generic coil to try, and written on the side was 'use with a ballast resistor' which I didn't see until I removed it. Time to get a resistor.

In the meantime, I fitted the original 28IMB on the car. With the Pertronix in, the old original coil, and the fuel filter on the pressure side of the pump, the car runs. I can't say it is great, but it does drive. The high RPM miss is gone (for the moment.) The car surges, especially under light load. The fuel filter looks nothing like Vitesse' picture. Mine is cheap, plastic, vertical filter that is 1/5 full and bubbling away like champagne. So...today I'll remove and block off the return line for good and run a new fuel hose to the pump. Maybe that is causing the aeration.

Many thanks for the help. I'll be enjoying the little car soon, but only for a few more weeks. Snow season is coming.

 

[the hobbler]

Afternoon Marcus;
When I bought my 500 it had already got a 652cc 126 engine installed, but the fuel return system between the tank and carb had been cut out at the tank. I re-installed the system at the carb by simply fitting a 'T' piece in the fuel line in the engine bay and connecting this to the return outlet on the carb. The 'T' piece was secured to the side of the engine bay with 2 'P' clamps (1 either side of the 'T' piece) and the return fuel line was then routed behind the cooling-air tube, protected from chafe by running the fuel pipe through some appropriately sized water hose (again securely located with a couple of 'P' clamps). This system does allow any surplus fuel to be 're circled' which helps keep it cool---I haven't had a moments trouble with this system.

 

[Vitesse]

Great news Marcus. See if you can get yourself a metal and glass filter. I have read horror stories about the plastic ones getting hot and expanding to the size of oranges.

When you have spent all that money on a nice new engine it would be a nightmare if that happened. In the UK they only cost about £5.00.

Tony

 

[marcus550]

Finding a fuel filter here in the U.S. to fit such small fuel lines led me to a lawnmower shop! This is a John Deere fuel filter to get me going. Guess I should try harder to find a nice filter, eh? I did buy a fuel pressure tester and it showed 3.5psi from the pump alone.

 

[Vitesse]

Finding a fuel filter here in the U.S. to fit such small fuel lines led me to a lawnmower shop! This is a John Deere fuel filter to get me going. Guess I should try harder to find a nice filter, eh? I did buy a fuel pressure tester and it showed 3.5psi from the pump alone.

There are lots of them on EBay in the US on the link below. Most from Hong Kong or China but some from the UK with free shipping. 1/4 or 6mm is what you want.

http://www.ebay.com/sch/i.html?_odk...1/4&_nkw=chrome+fuel+filter+1/4&_sacat=159912