Stalling when hot wont tick over, Carb engine

[martinnitram]

Morning,

I'm down in south of france touring in my motorhome, Talbot Express 2.0 petrol, and now its playing up when we are furthest from home.

It's a basic engine, single carb with manual choke, there is no ecu just a basic electronic ignition, with standard distributor cap and no points.

Recent replacement bits inc leads, plugs, dizzy cap, coil, all service items inc fuel and air filter, so its well maintained and im not suspecting these components .. yet.

The pattern that's emerged over last couple of days is this,

Starts from cold and runs as normal, we get on the motorway and do a couple hundred miles
Go through toll booths pull up for fuel etc ticks over no problem.

As the journey progresses when you lift of the gas to slow the engine stalls, if im carrying enough momentum i can drop a gear and bump start it while rolling and the engine fires again with a loud bang from the exhaust.
However once cruising again it runs fine with higher revs, it wont stall when you lift off above 2k rpm ( guessing as no rev counter)

When coasting on the over run it pops and grumbles slightly, and has always done this, and then as the revs drop and you go to accelerate it wont always catch for a second or two and that's when it bangs and fires again, when going slowly in 2nd and third at low revs you cant catch it when it stalls and you grind to a stop, which is annoying at best and dangerous at worst when it does it across a left hand junction.

So in summary,
starts and runs well from cold, as the engine heats up after a long run it starts stalling at low revs, not just tick over it stalls as the engine is coasting and needs a few throttle presses to get it to fire again.

I'm down here all week so hopefully some one will give me some pointers

Thanks

[GreenV8S]

Have you checked the plugs recently? I wonder whether it may be running cold during the sustained low-load run and then fouling during the overrun. If you have any spares with you it would be worth trying some clean ones to see whether it helps.

[Mignon]

Sounds like either idle mixture is rich or float level is too low.

[E-bmw]

I was thinking along very similar lines, needle valve as in affecting float level.

You may just have to drive through it for the moment unless you have the tools & can get the bits for a carb refurb kit.

[martinnitram]

Thanks for the replies

Good point on the plugs ill get them out, i have some tools, although on the motorway this thing with its 70 bhp (from new) is mostly flat out all the way.

Carb float level im not able to check but im going to try and clear out the jets by revving up and strangling it with a cloth over the intake a few times, may clear anything there.

Ignition coil has been weeping its oil, not sure how much its lost i can still hear it sloshing about inside so will replace this before i set off again.- is this likely to cause my symptoms ?

I feel convinced its some thing breaking down due to heat, it takes a good 3 hours running before it starts playing up

Ive got breakdown cover but its only any use for dragging you off the motorway, and there is a local French speaking garage As a last resort

Cheers so far.

[Hainey]

I know that carb, my old boss had exactly the same motorhome! Good news is that its a simple wee thing.

Check your accelerator jet and mechanism.

Check the float valve level. The needle valve is adjustable on these and can get sticky.

Check your not getting fuel evaporation from the bowl when it's left to heat soak (the old Renault 5 gtt problem) and hence needs a level reset.

[martinnitram]

Hainey said:

I know that carb, my old boss had exactly the same motorhome! Good news is that its a simple wee thing.

Check your accelerator jet and mechanism.

• with air cleaner off it squirts petrol down the throat when accelerator pressed*

Check the float valve level. The needle valve is adjustable on these and can get sticky.

• Any links on how to do this?*

Check your not getting fuel evaporation from the bowl when it's left to heat soak (the old Renault 5 gtt problem) and hence needs a level reset.

• Would this happen while on the overrun ? And not under open throttle ?*

Thanks for your help