Spitfire Mk4 stalling and then not starting

[John L]

The engine cuts out after a short run and stop, then refuses to restart unless I revert to using Holts Easy Start keeping the throttle full open then turning the engine over. 

The car is fairly new to me. Once running the engine runs well. I wonder if it is running a bit rich as checking the plugs reveals a dark black surround although the electrodes themselves seem okay.

Have checked the battery and the alternator is working okay. Before I start replacing parts which may not need replacing any tips as to how to proceed much appreciated.

Thanks

[johny]

So is this right - it starts ok cold but then when warmed it wont restart without the easy start?

[Alan J]

I have started having similar problem with 1600cc Vitesse based Spartan.  Car going like a dream, but stop for more than 10 mins when hot and she will not start on key until cool again.   I have bump started her a couple of times and carried on with the day out.

The car starts fine from cold, where do I start looking?

Alan

[johny]

One of the root causes can be compression which if low becomes worse when the engines hot then obviously the hotter the engine runs the worse the problem. Worth doing a compression test to discount this.... 

[Alan J]

Thanks Johny, I will start with that.

Alan

[Pete Lewis]

running rich will cause hot restart problems 

lean it off 1/2 a turn and see if the plug colour improves 

use of choke will take a good few hot miles to clear the soot.

on the 1600 spartan is this on strombergs or downdraft solex carbs ??

one thing to always check is the coil wired polarity correct ??   ie neg to dizzy pos to ign switch 

Pete

[John L]

Jonny, yes starting from cold using some choke is okay and the engine will warm up normally. 

But when the engine is hot the engine will either start momentarily and then cut out or will not start at-all so I have to resort to Easy Start. 

Thanks for your advice re a compression test.

Pete, also noted re running rich.

Will carry out some more investigation.

Thanks

John

 

 

[Pete Lewis]

one thing we have not mentioned is please check that after using choke that the jet does fully return 

to its adjusting nut    SU choke controls are a mishmash of hopeless rods and levers 

a quick prod with the finger to give the jet a poke will test if its going to pop back up or ..its all ok

Pete

[Colin Lindsay]

Last time I had a problem like that was the GT6 MK3, I adjusted the carbs slightly too much and they flooded after about 20 miles, then wouldn't restart util the fuel had evaporated again. 

[johny]

1 hour ago, John L said:

Jonny, yes starting from cold using some choke is okay and the engine will warm up normally. 

But when the engine is hot the engine will either start momentarily and then cut out or will not start at-all so I have to resort to Easy Start. 

Thanks for your advice re a compression test.

Pete, also noted re running rich.

Will carry out some more investigation.

Thanks

John

If it needs Easy Start I wouldnt have thought its too rich but just the opposite🤔 One controversial thing that some owners suspect is vapour lock in the fuel system where the pump or lines have got hot enough (35º and upwards) while stopped to allow boiling.

Must admit I cheat on my Vitesse and run the electric fan for 30 seconds after stopping (too much and needs choke to restart!) which makes for much easier hot restarts...

[Alan J]

Pete

The 1600 Spartan is running on Stromberg CD150 carbs that I was told were from a later 2ltr.  However when I had them off a couple of years ago to service them, I found from the Zenith ref catalogue that the ID No 3161 on one of the carbs dates back to a Hillman Minx 1500/1725 from 1967 to 1972.  The other carb has no ref no on, but is he same.

The coil polarity is correct.

The Delco distributor has Powerspark K26 electronic ignition within. I have fitted a new distributor cap today, just because I have had one for about 8 years.  I have a new set of plugs ordered, I will do the compression test when I fit them.

Should I stick with recommended plug gap of 0.025" using this electronic ignition? It has been suggested the gap should be opened up a little.

Thanks for your input.

Alan

[Pete Lewis]

it doesnt matter much what car the base carb was from what does matter is has it been converted to

the correct spec for a 1600

the 1600 stroms do not have a damper/air  piston spring but do have a thicker(heavier) diaphragm

ring .   1600  needles are  normally  7B    if you have pancake filters thats a whole can of worms 

with little to advise on what if any needles are available   

Pete

[johny]

12 hours ago, Alan J said:

Should I stick with recommended plug gap of 0.025" using this electronic ignition? It has been suggested the gap should be opened up a little.

Thanks for your input.

Alan

If youre using a standard coil I would stick with usual plug gap...

[Alan J]

Blimey Pete, that really is a can of worms then.

The car is going like a dream. 

When I serviced the carbs some years ago I could not understand why there were no springs in the damper, but as I had ordered the correct springs from the Minx list I fitted them.  I have no idea what the needles are. No problem with the running of the car since. 

I had gone into the cabs as it was always running too rich, I suspect that fitting an electric solid state fuel pump some years before was causing my problems so had fitted a pressure regulator/filter and everything seems to be fine with the mixture now.

I do have pancake filters, with only wire mesh as the filter.  I clean them occasionally.

My hot starting problem has only happened the last three runs out after about 40 minutes stops and a bump start has put me right.  If I stop for 5 mins for fuel etc. she starts again just fine.

All good fun.

[Alan J]

3 hours ago, Pete Lewis said:

it doesnt matter much what car the base carb was from what does matter is has it been converted to

the correct spec for a 1600

the 1600 stroms do not have a damper/air  piston spring but do have a thicker(heavier) diaphragm

ring .   1600  needles are  normally  7B    if you have pancake filters thats a whole can of worms 

with little to advise on what if any needles are available   

Pete

 

[Alan J]

• 
• TSSC Member
• 
• •  4
• Location Gloucestershire

Posted 15 minutes ago

Blimey Pete, that really is a can of worms then.

The car is going like a dream. 

When I serviced the carbs some years ago I could not understand why there were no springs in the damper, but as I had ordered the correct springs from the Minx list I fitted them.  I have no idea what the needles are. No problem with the running of the car since. 

I had gone into the cabs as it was always running too rich, I suspect that fitting an electric solid state fuel pump some years before was causing my problems so had fitted a pressure regulator/filter and everything seems to be fine with the mixture now.

I do have pancake filters, with only wire mesh as the filter.  I clean them occasionally.

My hot starting problem has only happened the last three runs out after about 40 minutes stops and a bump start has put me right.  If I stop for 5 mins for fuel etc. she starts again just fine.

All good fun.

[Pete Lewis]

7 hours ago, Alan J said:

always running too rich,

springs do actually richen the mixture as the air velocity under the piston is increased and you pull

more fuel from the jet

rich running will give you hot starting problems you need to find just what needle spec is fitted

the hunter with 1725 cc pulls more air than  the 1600...

having pancake filter then that weaken the mixture as you reduce the vacuum in the intake

so adding a spring may actually help the pancake ...all  good for headaches 

[Alan J]

Pete / Johny

Thanks for input, still hoping to avoid headaches! 

Compression test done today, twice with different gauges just to be sure. One gauge gave 160 to 165 lb sq" over all 6 cyl, the other gauge 170 to 175 lb sq" over all cyl.  I have no idea when the gauges were last calibrated, if ever, but at least results were consistent.

New plugs fitted today.

From what you say Pete the springs may help with the pancake filters, so I will try and get a run out soon, have a leisurely coffee break, then see how she starts before messing with mixture.

I will let you know.

Alan

 

[Steve P]

Sounds like floating debris in the tank blocking the pickup.

S

[Pete Lewis]

are both carbs ex rootes group    if so both will have a choke starting valve and there will also be a push and twist choke stop to give you summer/winter choke travel

triumph never fitted that refinement  small brass knurled  knob  with spring you push in and turn to reposition the choke stop ,,,quite clever

if you have two starting chokes  do you have a twin cable to operate both together ????   

(with an avid hate of pancack filters )

Pete

[Dick Twitchen]

56 minutes ago, Steve P said:

Sounds like floating debris in the tank blocking the pickup.

Good tip John.  I had something similar several years ago and eventually found a piece of neutrally buoyant plastic wrapper in the tank that would sometimes settle over the outlet, then 'float' away.

Dick

[Pete Lewis]

and dont discount the dreaded rubber slivers you slice off every time you refit s chap nassty fuel hose

they float about in the supply lines and block the back of the float valve

and they breed like rabbits 

Pete

[Iain T]

When it next happens take the hose off the fuel line to the carbs and with the ignition on the electric pump should spurt fuel out (take a handy container). If it doesn't there's the fault. I've had the same problem traced to electric pump fitted too close to the block so it vapour locked (at Duxford TSSC meet) then an intermittent break in the wiring to the pump, that was a head scratcher. I had a TR3A with SUs that was also a right PITA to start from hot and never fully solved the problem. I wish I had the forum to help then but the microchip hadn't been invented......

Good luck

Iain 

[John L]

Thanks for the feedback on the Spitfire starting problem ; so after further investigation the culprit turned out to be the Accuspark ignition kit - once this was replaced starting issue disappeared. 

It threw me as I was still getting a spark at the plug but to be honest I just did not consider the electronic ignition initially although now I seem to remember reading they can fail now and then and to carry a spare in the car !

Learning continues !

[micklewis]

On 22/04/2024 at 20:28, Alan J said:

I have started having similar problem with 1600cc Vitesse based Spartan.  Car going like a dream, but stop for more than 10 mins when hot and she will not start on key until cool again.   I have bump started her a couple of times and carried on with the day out.

The car starts fine from cold, where do I start looking?

Alan

1st thing check that the coil is wired correctly ,  if you think the electronic  ign is playing up dont fit accu spark , 123 or chinese surefire . fit either aldon or illuminetion !!