Ignition problems

[will]

I've had a 79 TL for about two months now after some of your advise on buying one. She's going well, but I'm have problems with the ignition. I've changed the spark plugs and cleaned the distributer cap and that made a difference. The engine starts first time from cold. But once it's warm and with starting and stopping the engine doesn't fire up straight off. Often needs 3-4 goes. Does anyone know what's going on here? What should I be looking at?

Thanks

Will

 

[malcolm]

Hot starting tends to be due to fuel problems. On most cars it's due to the carburettor getting too hot and the fuel in the float chamber vaporising. It's not a problem I've had in a Renault 4. The engine bay is quite open and the exhaust doesn't spend too much time in there.

Have you tried using full throttle to start the thing when it's hot (that helps for the hot inlet manifold)?

 

[angel]

What type of carb do you have? It seems like flooding, which is rather common on R4s when hot, especially those fitted with Zenith 28IF carbs.

 

[will]

I do have a Zenith 281F carb. So what should I do? I'm not a particularly confidient mechanic, I understood carbs are pretty complicated things.
Thanks for any tips.

 

[angel]

First replace the float needle valve, adjusting its height to 8.4mm (carburettor lid machined surface to top of needle valve ball).If you can still see no difference, there is a modification to the fuel lines that Renault suggested (see attached picture) especially for these circumstances, wherehigh underbonnet temperature causes fuel vapors inside the fuel pump and carb. All parts are standard except maybe the T-union with the calibrated hole, if anyone knows where to find it, or the dimension of the orifice, please post a message.

 

[will]

Thanks Angel

I'll have a go with your suggestions

Will

 

[Mike from Spain]

Try swapping the coil.

 

[Enrique]

I once read "90% of carburetor problems are electrical".
Since I installed an electronic ignition and a powerful coil I've had close to no problems starting the engine, whatever the temperature.

 

[AdamWilkes]

I've had some hot-start issues with my F6, so I am trying the fuel-line loop as above. I used a pair of brass 6mm T's, then I soldered over one hole of one T, then drilled a 1.5mm hole in the solder. Runs fine so far, but early days so I will report again. Pipework now routed forward of the engine, along the gear-rod support cross-member, and, unfortunately, over the exhaust (though I have heat-insulation-wrapped the manifold-to-inner-wing section of exhaust pipe anyway). Seemed tidier in the end than over the engine (and heater pipes etc). Am glad not to have pressurised pipes sat in a hot engine bay anyway!

Anyone have a spare Zenith 28if v05083 they would like to sell ? - mine vanished sometime in pre-history and I have a carb from a 945cc (without vacuum take-of point) instead! Runs OK, but I'd rather have the 'right' one - they seem to be available sometimes in France, but I have had no joy at all with sellers wanting to post to UK.​

 

[AdamWilkes]

.............but clearly a 1.5mm hole was too large. Started and ran fine with new empty pipework (but full fuel pump), and then refused to pump any fuel the next morning. I did notice that the fuel travelling into the clear fuel filter was a little 'splashy' (full of air); I guess air in the pump and being able to suck through the 1.5mm hole in the pipework was too much - I shall have to find a smaller drill bit!
I also have a Ducellier alternator that has stopped charging; brushes I think. Any spares available?