Crossflow Cutting Out When Hot

[Ray Stewart]

My 1600 crossflow stutters and finally cuts out when hot and idling, e.g. in slow traffic. It starts up again after cooling down for 10 mins or so but is then very lumpy until left to cool for a good while. I have checked the idle mixture screws and done my best to balance carbs with my balancing tool. It seems OK when I'm adjusting, even though it gets very hot and fan cuts in but still have the same problem when out on runs.

 

Could there be something else causing the problem?

 

Many thanks

Ray

[Manxseven]

check the coil

 

Caterham Fireblade here

[DaveMorris]

Coil is prime suspect - they can break-down when hot.

Alternatively - some people have had similar problems/symptoms with petrol vapourising in the carbs when underbonnet temps get really hot.

 

X-flow(er) power now resting. Trying Vx for a change.

[Ray Stewart]

Hi Dave and Manxseven

 

Many thanks for advice. Is there an easy way of testing if the coil is faulty?

 

Ray

[shn7]

Ray,

 

Hope you get it sorted. I think the answer to your latest question is yes, replace it ☹️

 

Steve.

Sussex (West) AO

Not forgetting Percy the Polar Bear

[andy couchman]

Also check that the carbs are not on too tight. They are held on by studs and nuts with rubber washers. If done up too tight you can get similar systems. Try loosening the nuts a bit - you should be able to rock the carbs on the inlet manifold.

 

Andy

[Billyboy]

after mucho head scratching a long time ago this was the cause of problems on a Lotus esprit with twin delortos the numpty who had replaced the carbs tightened them up too tight on the rubber mounts and the vibration of the engine was airating the fuel in the float chambers...........................amazing difference when carbs loosened up on the mounts

 

memories 😶‍🌫️

[ian.hoper]

Hi

had same problem in hot weather when I first got my seven .

Found that when it got very hot in traffic the fuel vaporised and had to stop for 10 mins to cool down .

Moved the fuel line away from the engine block into the air stram and cured it together with water wetter and a new tripple core rad I have to mention .

Check the fuel is being pumped up suficiently also ..

I got hold of a large jam jar and disconected the feed into the carbs then switched ignition on to see if the fuel flowed freely .

 

[Ray Stewart]

Hi all

 

Thanks again for your comments. I'll check the carbs aren't too tight but the problem has only just started and I haven't tightened the nuts on the carbs. Also the fuel line is still in same place. I've removed the thermostat to see if that has any effect by keeping the engine cooler but I'll have to put it back in before the cold weather, so not a permanent fix. Fuel pump is mechanical so can't check the flow without running car.

 

May have to try changing the coil but it seems a shame to buy one if it's not the cause.

 

Ray

[DaveMorris]

Ray,

if you're on a standard coil then it is worth upgrading to a high energy one anyway. They're not that expensive (in the overall scheme of things).

Alternatively I have an old, but definitely serviceable, standard energy coil which you can have for the postage cost.

Blatmail me if interested

 

X-flow(er) power now resting. Trying Vx for a change.