MatraSport Forum

Hi all,
My 1.6 starts perfectly every time from cold with the choke on full, even in this damp weather. However, when hot, it is not so good. I have found, with no choke and the excellorator depressed two thirds it helps but still takes a while to catch. Is it my car or am I missing carboretta knowledge?
Any input would be welcome, thanks.
Titus.

This is the kind of problems that were common in the old days, but with computerized engines is something people just don't mess with.

Are you using choke to start it from warm? You shouldn't do that, or it will be too rich.
A single full depression of the pedal, then release, then crank, should be enough to get it running even from warm.

But if that doesn't help, I would check ignition. If that doesn't help either, cleaning and gasket replacement of the carburettor would be my next step.

- Anders

Thanks Anders.

If the engne is real hot one problem can be fuel vapor in the fuel pipes and the carburator. After cranking for a while you get the system filled up with fuel again. (an electric fuel pump will help)

Hans

Since it starts O.K. from cold and in the damp, we know the electrics are fine, so your problem is with the fuel system.  It is normal for a fixed jet carb. engine when really hot to be slightly rich owing to the expansion of the hot fuel in the float chamber spilling into the manifold via the venturis, but if the float level is correct it should not cause too much problem.  Slowly opening the throttle to two thirds or even full open, and then cranking the engine will allow more air in too weaken the over-rich condition and allow quick starting.  You do NOT want to pump the throttle as that will inject more fuel making the rich condition worse.

I suspect that the float level is slightly too high causing too much richness making hot starting worse.  Either that or there is a leak into the system, which may be because of a poor gasket or seal.  So you need to carefully strip and check the carb. and if necessary re-set the float level, then try it again.

Roy

Thank you Roy,
I have found with throttle fully down, as you say (not 2 thirds) it fires pretty well. I did strip and clean the carb when I got it 2 months ago- much needed as it was filthy, and changed the fuel filter. I didn't check/ change the gasket or reset the float as this was beyond my skills/knowledge. I will relook at the gasket but any advice as to the float setting?
Would have attended the 2 Dec meet but forcast too wet for me to drive that distance.
Many thanks.
Titus.