Reluctance Of Engine To Start

[Mike Allfrey]

Currently, with my Jupiter there is a considerable reluctance for the engine to start from (relatively, not freezing) cold situations after standing for a week or so with a trickle battery charger connected. This involves full choke and six or seven lengthy sessions with the starter motor - sort of to the extent that there is concern for the batteries and ring-gear. Once the engine has fired, even if still cold, the engine fires up instantly and, when warmed up, I sometimes wonder if the starter pinion has actually engaged with the ring gear.

At cold starts, I watch the oil pressure warning light flicker in time to the clicks of the S.U. petrol pump. My Jupiter has a security device that allows a period of time to start the engine after the remote control is pressed to activate ignition circuit devices.

My thoughts have been aligned with fuel starvation issues or the security device. However, the Jupiter was driven up a long, steepish, climb at high revs in third gear and there was no indication of gasping for fuel, which my Rover V8 used to exhibit when the reserve tap migrated towards mid-position (off) and caused the engine to virtually cut out on a hill.

There is also a local Javelin exhibiting the same symptoms, but I am not sure if it has a security device like mine.

Any suggestions out there?

Mike Allfrey.

[p.p.]

the same happens to my javelin, after 5 session with the starter motor.... it gets quicker startet when i pump the petrol at the petrol pump!
i dont worry about.
so the oil starts to cirquit the engine, it is normal to racing car to get the oil going befor you start the engine!!! get a strong and top quality batterie,i also got a new starter and alternator, its help's! disengage the cluch and gear in neutral.
sorry not helping to resolve the problem but getting easyer to the brain.....

[Mike Allfrey]

Hello Peter,

Thank you for your comments - so, I am not alone!

I have just written to BP Australia about my concern and am looking forward to their response. There is one very interesting aspect to this subject that I have just realised. Some years ago, BP Australia issued a bulletin describing the characteristics of their BP Ultimate 98 petrol. I do not know if you get that petrol in Switzerland, but the original bulletin stated that the petrol had a shelf life of four to five months, depending on how it is stored. Apparently air in a container can evaporate off all the flammables if the container is vented to atmosphere as are Jowett petrol tanks and carburettors. Recently, BP Australia issued a revised bulletin (I think it was aimed at lawn mower users and such - but the same applies to us as well). The essence of the later bulletin is that the shelf life has been reduced to just 5 weeks and less, in vented containers.

I will advise this forum what response I receive from BP Australia. They have been good to me in the past. Wakefield's Castrol were also very helpful with regard to oil questions.

Viele grusse (can't do umlauts on here!),

Mike Allfrey.

[p.p.]

jambo Mike,

yes this is a problem!!! !!

but not for me, i use the javelin lots of time. in the winter time will drive if there is no snow and no salt on the road....( iam not in the mountain)
the winter gets hardly any snow anymore in my place....change of weather....

take it easy

peter

[Keith Clements]

We will be interested in BPs reply.

Modern petrols contain less volatile components than those of the 1970s but I would have thought more than those of the pool petrol days when Jowetts were designed. Petrol sitting in the float chambers for a few weeks may well have lost sufficient volatility to ignite the mixture when cold.

However, there may be other things at play. My SA with DelOrto carbs rarely has problems firing, even without the choke on, but the Jav and SC do which both have rebuilt Zeniths with choke and the same distributor. Could it be that one of the passageways in the carb suffers after prolonged inactivity? Or could it be the mixture is wrong when cold? One would have thought the action of the choke would far outweigh any issue with the carb body or petrol...but perhaps not.

I also notice that the SC and Javelin engines sometimes fire on first or second rev but immediately die and then take a few more turns before springing into life. They also need some ether Easystart if left for more than a couple of months.

The SC (and possibly Jav) may have a modified cam in them which could be an issue. Both their engines are due for a rebuild/replacement so we will see.

[Srenner]

Same thing with my cars with Zeniths. Instant running if it was started during the day; let one sit over night and starts on the button and then dies, requiring a second or third attempt. Let it sit for weeks and might as well grab the ether.

KC is right about the "thinner" gas, which effectively means your carb is too lean. When SoCal went to ethanol blends ( what a scam) we had to jet all the cars to a larger size.

Don't get me started on oil.

[Forumadmin]

Well tried to start the Jav today ..20 turns of engine with choke. not a glimmer. Easystart fires first time but dies . Repeat three times. Get petrol can out which contains petrol slightly older than that in tank i.e. 7 months.
Take 20 ml out in syringe and put 10ml down each air intake. Fires first time and continues and ticks over beautifully.????????

[BarryCambs]

Myself and some friends have had various problems with modern fuels going off. Problem is, there seems to be no rule and different vehicles seem to react differently to storage. My friend has several bikes. Two of them stood side by side in the same shed with ethanol free fuel from the same jerry can in them for 3 months. The Ducati wouldn't even fire, but once the carb was drained and refilled, went first kick. The Honda next to it went first time. The Long Two becomes difficult to start after about 3 weeks. The first time I had this issue, once I did start it I thought it had water in the petrol or a blocked jet as it was coughing and spluttering and very unhappy. I nursed it to the petrol station and as soon as I restarted, it ran like a well oiled clock! My friend has a 1959 Zephyr which stands for months at a time and fires up and runs well without any problems at all, as does another friend with a TR4.

The Long Two is used pretty much weekly now, so it's not a problem. The carb has no gasket between the float bowl and body and there's always a good smell of petrol in the garage, so I suspect the volatile parts of the fuel evaporate quite quickly. Looking at the problems we've had with various motorbikes, cars etc, those using lead replacement/ethanol neutraliser additives seems to fare no better or worse.

Somewhere I have a document from Shell's own laboratory which I'll try and dig out. They were looking at shelf life of the fuels, specifically for outboards/marine use and as I remember, they recommended 3 weeks for storage once in the tank. I'm sure I've seen fuel additives for storage, but I've not tried them.

[BarryCambs]

The could have been what I was thinking of

https://www.bp.com/.../dam/...services/ ... ndling.pdf

https://www.classic-oils.net/TetraBoost ... e-Extender

[Mike Allfrey]

Hello Folk,
I have received a very good reply from BP Australia and they have offered to do a presentation on the subject at one of our Association of Motoring Clubs (AOMC) functions, hopefully at the AOMC Restoration Seminar on Saturday 29th June.
This problem does not only concern us, but also lawn mower operators and boat owners. Imagine pulling on the rope of a Seagull outboard engine until it fires! After three new ropes . . .
I will put together my correspondence with BP Australia when it is finished. One tip, in my initial message I attached a photo of my Jupiter and I think that triggered the good response. In answer to their response, I attached a photo of the Jupiter carburettor installation and that drew the reply that the installation is a prime candidate for boiling off the lighter components in the fuel and that the Zeniths have vents that encourage quick evaporation when the hot engine is stopped.
Watch this space!
Mike Allfrey.

[Mike Allfrey]

One point about 'Easy Start', 'Aero Start' and such, great care needs to be taken when using those starting aids. I have seen visibly bent connecting rods after excessive doses.
Then there was the farmer up in the Mendip Hills who ran his TEA Ferguson tractor on paint thinners during the Suez Crisis - what a mess that was!
Mike A.

[Mike Allfrey]

Below, hopefully, is my correspondence with BP Australia to date.

Initiating Message:

Dear Sir or Madam,

I am a customer who, where possible, runs my motor cars exclusively using BP Ultimate Unleaded 98 petrol. My everyday car is a 2001 Rover 75 and I have no concerns with that.
However, I also run a 1950 Jowett Jupiter as a hobby motor car, and due to its status, it can sit unused for a week or more. The engine is a horizontally-opposed 1½ litre four cylinder unit with two Zenith down draught carburettors. The concern that I am currently experiencing is that, after standing for a week or more, the engine is very difficult to start from cold (whatever the Melbourne ambient temperature may be – summer or winter). The engine usually requires six or seven lengthy sessions of starter motor cranking before it will fire. It gets to the stage where I worry about the starter motor and the batteries. Once started, if immediately stopped and re-started, it starts instantly. That is the same after non-use for two days, instant cold starting. When the engine is warmed-through it continues to start instantly.

The engine has been fitted with an electronic ignition system, and that produces a really good spark. In addition, there is no evidence of carburettor flooding.

Currently, I am wondering if the petrol that is left in the carburettor float bowls while the car awaits its next outing, maybe deteriorates to the extent that I have to 'crank' the carburettor bowls' contents through the engine until flow from the fuel tank arrives and then the engine commences to start. Could my assumption be correct?

I have tried using the Sta-Bil petrol additive as a means of improving the situation, but that seems to make no difference at all.

Your comments on this subject will be greatly appreciated.

Yours sincerely,

Michael Allfrey.

First Response From BP Australia:

Hi Michael

Thank you for your enquiry. Nice car !
What you are describing is an issue with the volatility of the fuel. Do you remember when you filled up the fuel tank? Also, how frequently do you refuel the vehicle? And do you fill the fuel tank fully up?

Petrol is a blend of over 100+ different chemical molecules. Each different molecule has its own volatility, boiling point, energy released on combustion, RON number, MON number and other properties.

The link below gives an indication of what a distillation curve looks like.

r.jpg

https://www.bing.com/images/search?view ... =0&eim=1,6

What could be happening is the fuel is a winter blend which has lighter components blended in. Some of these lighter components of the petrol in the fuel tank have evaporated out over the summer / warmer months.

In addition to this, some of the light components which are still in the petrol in the fuel tank have a second opportunity to evaporate when the fuel is sitting in the fuel bowl of the carburettor.
Where are the carburettors located in the engine bay? Above the engine or in another position which gets warm?

After running the vehicle, the heat in the engine bay will assist in boiling off additional light components.

We are looking at the T0 to T20% part of the distillation curve.

When the air and fuel mixture goes into the cylinder, the petrol needs to vaporise and this will result in good combustion. When starting the engine from cold, the light ends vaporise first and will ignite with the aid of the spark. From then on, the flame front spreads out, heat in the cylinder increases due to combustion and increasing pressure in the cylinder. The mid-range and heavy ends will be burning and vaporising until combustion is finished.

Following your description – for the first 6 to 7 cranks the old fuel is being drawn into the cold engine and when the spark plug sparks, the conditions for combustion are not good and the initial combustion doesn’t.

After the 6 to 7 cranks fresher fuel is going into the engine and combustion starts occurring. That said, the previous 6 to 7 cranks have left fuel residue in the combustion chamber and the chamber is very rich in its fuel mix. The fuel starts to burn but when the temperature gets hot enough the mid-range and heavy ends evaporate and all of the sudden the mixture is too rich to sustain combustion. Rough running and then the engine will stop.

The next few cranks now have fresh fuel and less residual fuel in the combustion chamber. Initial burning occurs and the residual fuel in the combustion chamber has leaned out allowing the charge to burn more completely. The engine is now running but maybe a bit rough which then settles down as the engine warms up and excess fuel is burnt away.

Once the engine is warm, restarting it is much easier. As the air / fuel goes into the combustion chamber, the heat of the chamber assists is evaporating the mid-range and heavy ends of the fuel – a bit like a glow plug in a diesel engine.

What to do then?

For the fuel tank - if you believe you have old winter petrol in the tank, take the car for a good drive to run the fuel level down or drain the tank. Fill up with fresh fuel. When filling the tank, don’t fully fill the tank. If possible, keep less fuel in the tank and top it up more often to keep the fuel fresh.

For the carburettors – if you can get access to the air inlet to the carbs, purchase a Starting Fluid from Autobarn, Supercheap Auto etc and follow the instructions, which will be along the line of spraying some product into the air filter or inlet to the carburettor. This will provide the missing light end of the petrol, get the engine started quicker and less flooding of the combustion chamber. Over time you will get a feel for how much spray is needed.

Check the jetting on your carb in regards using the choke and the idle jet.

Let me know how you go and I hope this is of assistance to you.

My Response To The Above:

Dear Malcolm,

Thank you for your very detailed response to my questions about difficult starting after my Jowett has stood for lengthy periods without use.
Attached is a photograph of an engine about the same as mine. The carburettors are located on the top faces of the cylinder heads. In the photo, the black dot to the left of the yellow arrow is the vent hole for the carburettor float chamber. I can well understand that the light components can either 'boil off' or evaporate over time after the engine is turned off.
I could not insert the photo - use imagination!
I will investigate a starting fluid to help the situation when starting after the car has stood for a week or so. In addition to that, I am in the process of another trial fix. The car has an electric S.U. petrol pump and, as a further security measure, I have wired the pump through an unused fog light switch on the dashboard. With the engine running, the petrol pump was switched off and the engine left running until it ceased to run due to fuel starvation, then the ignition was switched off. It is waiting for a week and then I will check to see how it starts after the pump has filled the float chambers.

All of this reminds me of when farm tractors were fueled with TVO (Kerosene) and the procedures we had to adopt to ensure cold starts.

I have tended to keep the tank nearly full, mainly to avoid condensation, but will certainly try your suggestion of adding fresh petrol from time to time.

I am the Jowett club's Delegate to the Association of Motoring Clubs (AOMC) which meets four times per year. Would you or someone from BP be happy to be a guest speaker, on this subject at a forthcoming AOMC Delegates' Meeting? I am sure that the Delegates would be very interested to hear about the use of modern petrol in vintage and classic cars. If so, I can make arrangements to suit.

Again, grateful thanks for your advice,
Michael Allfrey.


Second Response From BP Australia:

Hi Michael.

Thank you for your email and the attached picture.

The carburettor is perfectly positioned to be heated from the rising heat from the cylinders and also the vent hole for the carburettor float chamber assists in allowing vapour to be released.

Right: The photo I sent to BP Customer Care.

In our Fuel Technology Group, there is myself and Maria Tilling who are both able to present and speak on fuel, refinery operations, logistics, QA, fuel testing, BP Ultimate additive, etc.
I am more than happy to present at future AOMC meetings. Just let us know the date, time and location and I can confirm if Maria or I are able to present.

I like your idea to trial the running down of the fuel in the fuel bowl. I do the same thing with my garden blower and whipper snipper. Due to non-regular use, at the end of using them, I drain the fuel and then run the item till the fuel bowl is empty. For my mower, I run it with not much fuel. When I do run the mower, I top up the fuel with enough to mow my section i.e. addition of fresh fuel. I have not experienced issues with fuel gumming in any of the equipment and I use Ultimate 98. For the 2 stroke mix I use Castrol TTS full synthetic. The detergent additive in the Ultimate 98 is good for cleaning any deposits in the carburettors and inlet valves.

The fuel cans I use, seal very well and there are no petrol fumes in my garage in the summer or winter i.e. no vapour loss. I give the fuel container a good shake before opening it and decanting the fuel.

Please let me know how the trials go and how much starting fluid you need to use. Be careful as it can be very volatile and flammable !

[Mike Allfrey]

Further to all of the foregoing, BP strongly advise not filling your tank when there is a fuel delivery activity at a petrol sales outlet (they are not service stations anymore!). The reason for this advice is because the high petrol flow rate from a tanker stirs up sediment and algae growth in the underground tanks at the facility. They suggest going to the next BP outlet, or allow time for the grott to settle before filling a car's tank.

For what it is worth,

Mike A.

[Chris Spencer]

Reading through all of this - its certainly something that I have experienced on several occasions on the 4 cylinder engines and I have always been able to correct it - in just about every case its been down to the choke system - which is far from ideal & for some reason they don't always engage fully - Its the first thing that I check now and in the vast majority of cases its been the primary cause of non starting

[Keith Clements]

See the JCL tech bulletin on the subject recently brought up here and in the Jowetteer.