R4 - shudders/jumps and now won't start

[harbourseal]

On full choke, you can drive it and it doesn't cut.
Jacqueline

That might be a problem with false air. There is air coming in to the fuel system. Causing e very lean mixture.
That you have to use the choke to cut the air suply to the mixture says something.
Check al the hoses that run from the manifold and the rocker cover to the carburettor. are they attached right and are there no cracks in them. The T joint from the bigger hose on the rocker cover is the most suspect. a minor crack causes a lot of trouble.
If the hoses and T joint are ok, move on to the joints of the carburettor to the manifold.
There might be a crack in the plastic heat block in between the carburettor and the manifold. Or the paper gaskets are shot.

 

[André4Renaults]

There might be a crack in the plastic heat block in between the carburettor and the manifold. Or the paper gaskets are shot.

This is exactly where I think the problem may be. The 1108cc Renault engines were used in Daf 55 & 66 cars, of which I have more experience, and this was a frequent problem. If there's even a small air leak in the area then as the engine revs increase the air leak will become a flood, thus causing an instant stall!

 

[malcolm]

There's also the rubber vacuum hose that goes from the T piece to the inlet manifold. That needs a restrictor with a 1.5mm or something hole, or blocking completely else the engine will run really lean and need choke.

 

[Richnd1974]

Hello thanks Richnd1974 - we'll double check those too. We have managed to get it started now but need to look at the timing - any advice on how to do this would be appreciated

Search Renault 4 timing in YouTube there is a great video, easy to follow and had best results for me, where are you located