I was experiencing cold start problems and one of the members solved that problem. When I took the car out last week, we stopped at a plant seller (a 1 mile drive) for about 10 minutes. The car restarted fine. Wh then proceeded to a custard stand. The car was fully warmed up when we stopped. To restart, took at least a dozen attempts, I almost called for a tow. Any suggestions?

MJB

 

Check that your Otter switch on the Automatic enrichment device (AED/choke) is turning the AED off. The Otter switch is a Bimetal switch that is closed when cold allowing the AED to earth and function. When the engine heats up so does the Bimetal switch and it opens breaking the earth circuit on the AED which then switches off. If the Otter switch is broken and is not opening the AED will remain on and starting the engine will be a nightmare as too much fuel will be fed in to the combustion chamber. You can test the otter switch easily. When the engine is cold and you start the car the AED will click on and hiss loudly. When the engine is hot and the Otter switch is working the Otter switch will open breaking the circuit and the hissing stops. You can break the circuit yourself by removing the wire on the top of the Otter switch.

The other reason starting the car when hot is a problem is too much fuel from the carbs so check your carbs are set properly and not too rich. Check the floats are set to the correct height and that they are floating not filled with fuel as the brass ones can spring a leak and sink. Check your float valves are closing correctly. A small piece of dirt in the valve and they will allow fuel to pass into the float chamber which over flows in to the carb flooding them. The fuel level in the float chambers is level with the bottom of the carb needle valve so it does not over flow into the mouth of the carb. Hope this makes sense.

 

The car was retrofitted with a hand choke. Does this impact your advice?

MJB

 

I only use the choke when starting cold, then close.

MJB

 

Is the retrofitted hand choke like the one where it pulls down the main jet ?
When the car finally started, was the lots of black smoke, a little, or any at all ?

 

I didn't notice any smoke.

 

The Otter switch is malfunctioning. I ordered a replacement from Moss. It is rather pricey at $114. I will reply again after fitting the replacement.

MJB

 

Why do you need a new Otter switch if you have a manual choke or is your manual choke a switch & not a slider?



AED diagram.

 

If I understand you, a manual choke makes the Otter switch redundant? Is the Otter switch essentially an automatic choke?

 

We don't know enough about your car and what you mean by it has been fitted with a manual choke.

Is the car choked/enriched via the AED operated by an Otter switch or a manual on/off switch to turn the choke on and off.

or

Do you have a manual slider in your car that is connected to a cable that requires these to be fitted to each carb & pulls down the main jets against their diaphragms to choke/enrich?







Which is it?

 

If it didn't smoke after it started after 12 try's, it's probably not a choke problem (too rich), but we still need to know what kind of choke you have to totally eliminate that from the equation.
When it started, did it run rough or smooth ?
And when I mean rough, did it run on only a few cylinders at first with coaxing on the accelerator peddle to get it to idle, and even then, it took a bit of revving to clear the idle up ?

Glyn, that slider mechanism where it's labeled "HOT", where is there ever a situation that you have to have the choke on HOT, that' half way, isn't the choke still open ?
Where is there ever a situation where one would drive around with the choke half way on ?

I have that exact choke mechanism on my Bentley, it doesn't take long for the engine to be warm enough where I have had the choke on half way.

 

I would still say it is overly rich. Whether that is caused by the choke (AED) and Otter switch or by over flow from the float chambers can only be accessed once we know the set up of your manual choke.

 

Jeff. I can't answer for Jaguar's chosen labeling. That's an E Type but they have always chosen that labeling.







Choke escutcheon.

 

It is a push/pull cable attached to the Stromberg carbs. It is located adjacent to the bonnet opener cable.

 

Ah, OK, the Stromberg carbs are a totally different animal, I have no experience with them, but the must utilize a simple choke flap like a North American set up.
Assuming that they are a down draft carburetor.
In the HOT position the fast idle cam may still be in operation and still partially choked.

 

Oh! Strombergs. How often is this car used? Another issue might be fuel vapourisation when hot causing hard starting. You might still have a tank of winter gasoline that has more light ends to to aid cold starting in winter. Oilco's make Winter grade & Summer grade gasoline.

 

It is not driven as much as I would like. I use a fuel stabilizer and fill it with premium fuel.
MJB

 

That won't make any difference to content of light ends for winter or summer blends.

Suggest you drain the tank & fill with fuel blended for current ambient weather.

 

Weren't we talking about Otter Switches and adjusting the starting carburetor on an SU system on Mark's car.
How did we get to talking about Stromberg carbs ?
He doesn't have Stromberg's, right ?

 

His statement "It is a push/pull cable attached to the Stromberg carbs. It is located adjacent to the bonnet opener cable."

Maybe someone has fitted a pair of later US Jaguar Strombergs to his car.

Nevertheless ~ fuel vapourisation is another potential issue with hot starting.