S-4 engine won't turn over

[GingerClark]

One day, my 1969 S4, which had worked perfectly the day before, wouldn't start. She would crank over but not fire up. After topping up the Strombergs, (didn't work) Thought the problem might be in the aging, crumbling, fuel cell installed inside my gas tank. So I sent it off to be rebuilt. That was done, and installed, but the engine still won't start although it turns over beautifully.
Topped up the Strombergs, checked to be sure the gas was reaching the carbs, (filter not clogged) changed the spark plugs, checked compression (180/190), replaced the battery (it was due, anyway), checked for spark at the plugs with the anti-theft switch on and off (no spark and spark respectively). Sprayed ether into the intake. It started, ran very shortly, died. Didn't restart without the ether.
Could it be the carbs? And if so, is there some way that Strombergs commonly fail? All ideas and suggestions would be very welcome.

[richardcox_lotus]

In my experience, instant failure when all was well before is usually electrical rather than fuel. Although you've checked for spark, maybe the coil is breaking down ?

Or a Dodgy earth somewhere - maybe issue with starter solenoid ?

All things to check.

[AHM]

If the ignition switch is worn you can get starter but no spark - Rule this out by using the starter solenoid button with the ignition on.

What type of ignition do you have? Condenser failure?

[Bugeyed]

Sounds tricky, a way out thing to try-take out spark plugs and turn it over by hand to see if cam and valves are moving

[GingerClark]

In my experience, instant failure when all was well before is usually electrical rather than fuel. Although you've checked for spark, maybe the coil is breaking down ?

Or a Dodgy earth somewhere - maybe issue with starter solenoid ?

All things to check.

Thank you for your reply. That's a really good point and electrical failure was the first consideration. I kept thinking that the anti-theft switch had somehow failed on because that's what it acted like. But we've checked the spark and everything leading to it in every possible iteration and it's strong and reliable. Just don't think it's electrical. Ruling that out, it also acts just as thought the Strombergs aren't topped up. That's why I'm thinking a carb problem.

[GingerClark]

Sounds tricky, a way out thing to try-take out spark plugs and turn it over by hand to see if cam and valves are moving

Thank you. All moving.
We did get ignition and a short run with some ether (I'd forgotten how much I love the sound of that twin-cam)

[GingerClark]

If the ignition switch is worn you can get starter but no spark - Rule this out by using the starter solenoid button with the ignition on.

What type of ignition do you have? Condenser failure?

Thank you. It's all been checked. Gorgeous spark. Still think it's in the carbs since the engine started with ether but shut off shortly. Maybe fuel-starved.

[lotusS2guy]

Ginger
Are you still running a mechanical fuel pump? If so, can you get alight down on the glass fuel bowl and see if it is full. You might disconnect the fuel line and see if gas is spurting when the engine is turning on the starter. ( make sure you have a container for the fuel to spit into -- gasoline will ruin your manicure

Herb

[gjz30075]

Not sure what you mean by 'topping up the Strombergs'.

What happens if you lift either or both of the Stromberg dampers and squirt some starter fluild in. If you have spark, something should happen.

Greg Z

[GingerClark]

Ginger

Are you still running a mechanical fuel pump? If so, can you get alight down on the glass fuel bowl and see if it is full. You might disconnect the fuel line and see if gas is spurting when the engine is turning on the starter. ( make sure you have a container for the fuel to spit into -- gasoline will ruin your manicure

Herb

Hi Herb!
No, the fuel pump is electric and is set on 3. It's in the boot and it clicks merrily away when the switch is on. There's fuel spurting out of the line just before the carbs (that goes into the carbs).
Through it all my manicure, such as it is, has managed to maintain itself. Thank you for the warning.

[GingerClark]

Not sure what you mean by 'topping up the Strombergs'.

What happens if you lift either or both of the Stromberg dampers and squirt some starter fluild in. If you have spark, something should happen.

Greg Z

By topping up the Strombergs, I mean adding ATF to the fill line. Usually when the car won't start, the ATF in the carbs is low and this is a simple fix. (At least for me. Don't know about anyone else).

More and more I'm of the opinion that the flaky fuel cell left residue in the carbs, although there's no evidence of anything in the fuel filter so I could be wrong. If that really is the case, can it be cleared out without dismantling the carbs? If that's not the case, I'm still stumped.

[AHM]

What is the timing set to?

Anything will run on ether - That's why they sell it for starting cars

[billwill]

Could it be clogged jets?

[oldelanman]

Check if the plugs are wet or dry when you pull them after cranking the engine .... if dry it indicates lack of fuel. It could be the float valves are sticking .... try giving the carbs a sharp tap it may free them off.

Not the cause of your present problem but I think ATF is too thin for the dashpots, the workshop manual specifies engine oil.

[elansprint]

Are the diaphragms split in the carbs ?
Ian