Exciting new Amazon problem - please assist.

[Guest]

A very happy new year's shiteing to you all.If anyone could help diagnose a charming problem my Amazon has developed, I'd be very much obliged.The symptoms consist of the engine cutting out completely after a fast run. You'll be bowling along at 65-70, pull up to a junction and bang - engine dies. A lot of cranking and swearing gets it going again. Below this speed you can pull up to junctions happily and the revs don't cut.I'm beginning to think the fuel pump has had it and that it's starving the engine when you slow down. The way I've been dealing with this so far is to keep below 65 (takes a fugging age to get anywhere) or to blip the throttle when slowing down. Luckily my heel n' toe technique is coming on leaps and bounds

[Station]

Get a fuel pressure gauge to see if it is fuel related?

[Guest]

Get a fuel pressure gauge to see if it is fuel related?

Don't have one, but might be a worthy buy. What do you reckon, is my diagnosis right?

[Rocket88]

Easy [and cheaper] way to find out if it's fuel related.........Go out replicate the symptoms, when it happens, fire some Easy Start in. If it starts immediatley, it.s fuel, if it doesn't it's ......err not. Possibly coil/condensor related?

[Mr_Bo11ox]

Its not carburettor icing in this cold weather is it?If it was your fuel pump I would expect the problem to be more apparent during the 'bowling along' bit as thats when youre gonna need the most fuel.Next time it does it, just leap out and inspect the carb for external signs of frosty bits.

[whitevanman]

Carb iceing is what I would check out, fuel pump would have completely different characteristics I would have thought, lack of fuel would be rev related not speed as it is the engine load that would decide if it cut out or not. Same as Coil/condensor, I'd expect the coil at high revs and the condensor at low revs.....rough running and cutting out at low revs I'd check for a vacuum leak with WD40....hope you solve it Wat

[Mr Lobster]

I'd be tempted that its carb icing too. Had an Mk1 R5 years ago with a Pipercross airfilter that suffered from it, only ever happened if you were doing motorway speed so sounds pretty similar.

[dollywobbler]

Yup. I was also thinking carb icing. Might be worth making some sort of muff to reduce the size of the air intake at the front and see if that cures it.If you pull over, wait a few minutes and then it's fine, that could well be it.Not familiar with the design but some air intake systems have a flap so you can set the carb to draw air in from around the exhaust manifold area for this very reason. My old Renault 5 had such a system.

[Rusty Pelican]

Carb icing is an idea but what about evaporation , had this on an Imp once wherby the fast speeds caused the engine to run a little hotter than normal causing fuel to evaporate in the pump , just an idea

[Futuramic]

Yup. I was also thinking carb icing. Might be worth making some sort of muff to reduce the size of the air intake at the front and see if that cures it.

Phwoar! First naughty Amazons and then Muffs? I've got all hot under the collar.Anyway, sustained high speed running is a likely cause of the carb icing up. I'd have a look there first.

[CIH]

No idea about your probs but I think I saw you out in this maybe a couple of days ago ?

[Guest]

No idea about your probs but I think I saw you out in this maybe a couple of days ago ?

Wasn't me Pete. It's been parked in the garage for at least a week. There are quite a few Amazons knocking around here. The weather hasn't exactly been clement and there's been a load of salt on the roads. There's a baby blue 121 that lives in Sale allegedly, and a 222S estate in Sale Moor that's regularly used.

[Guest]

This cutting out problem has occured in all weathers - not just in the cold. The dashpot has been known to stick on occasion, so I will check to see if things are fuel tight.

[CIH]

We had one of those Roger Moore coupes in a while ago but green and no minilites. It was a bit rough, but cool.

[j-j]

+1 for carb icing!Could also be a little bit of shite in the carb temporarily blocking the jets of the first choke

[scruff]

Does it run OK off-choke at idle WAT? I would suggest a blocked jet too - has the idle speed screw un-done itself a bit?

[Richard]

If it has a dashpot doesn't that make it a Stromberg with only one jet?Is the needle secure in the dashpot?

[Rusty Pelican]

If its a Stromberg it wont work

[nigel bickle]

My 'olduns' are suffering all sorts of peculiar symproms right now - just putting it down to severe carb icing.Solved it by reverting to more moderns (well-early 80's) which seems to have cured it nicely. Got a heater,too!Back out there when its a bit warmer, for me anyway.

[wilko]

If it happens in all conditions & only happens when shedding speed from cruising, then either the carb needs a rebuild, or something is blocking up in response to a change in fuel pressure when you lift off the gas. Could be a bit of crap in the fuel system somewhere, but if none of the normal carb/pump/filter investigation produces a result, I'd change the rubber fuel lines - sometimes, these collapse internally (like rubber clutch pipes), and this can be a pig to diagnose as it tends to cause intermittent faults.

[garethj]

This cutting out problem has occured in all weathers - not just in the cold.

Carb icing can occur even when it's 5-10 degrees outside, you want a nice warm air feed into the intake, preferably one that can be blocked off in warmer weather. As Mr_Bo11ox says, when it happens have a quick look for signs of jack frost on the outside of the carb.