Help with a non-starting 3.8

[Treetrimmer]

For health reasons nothing has happened with my 1965 3.8 "S" for a couple of years.
I have now enlisted the help of my 16 year old grandson, ( off school now until September) and we are making progress again.
I have recently changed both the fuel tank sump filters; refurbished the fuel bowl in the engine bay, and I'm trying to get the engine to start.

We have checked we have a spark ( looks very healthy), removed the air cleaner and used Bradex "Easy start". The engine will not start. The battery is relatively new, and fully charged. The engine turns over well, and nearly starts, throwing the starter dog out. There appears to be a fuel leak on the A.E.D., as the black rubber cover over the solenoid gets wet ( presumably with petrol). The fuel bowl on the O/S inner wing is full, and both fuel pumps appear to be working. There is fresh fuel in both tanks. I imagine the fuel within the carburettor bowls would be stale.

So, I am at a bit of a loss to know how what to do next. Is there a way to prove the A.E.D. is working?

Please would someone provide a sensible way forward, perhaps to test things in a proper sequence. If the fuel in the carburettor bowls is stale, is there an easy way to replace it? The battery is back on charge, ready for another attempt.

Yours in hope, Richard the non-starter

[Glyn Ruck]

When last did the car run? Check anything you have touched since then. All you require is air, fresh fuel & spark at the right time, ~ and enrichment when cold.

Take the tops off of the float bowls & suck out any fuel. Check for cleanliness. sinking floats with fuel in them & set your float levels while you are about it. Clean inline filters & needles & seats for dirt/gum.

Strip & clean the AED ~ When operating properly it will hiss loudly. Adjust the AED needle for your ambient conditions.

Is the glass bowl on your fuel filter sealing properly? Check all unions.

While your fuel filter might be full are you sure you have 2 to 3 lbs fuel pressure & no air leaks in your fuel lines.

Are the fuel tanks full? The pick up pipes in the tanks rust through.

Is the timing correct? Is the firing order correct? Are your points & condenser in good order & gapped correctly? Remember number 1 cylinder is at the rear closest to the firewall.

Ensure spark plugs are clean & gapped correctly. Your coil seems fine.

Presume you have a WS Manual ~ if not download at the top of the forum under "S Type Documents" ~"Maintenance"


I had a similar issue until I found this on the left tank. There seemed to be plenty of fuel at the filter & carbs. (due to alcohol in fuel)

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[Treetrimmer]

Hi Glyn,

Thank you for taking the time to reply.
I'll work through your list, and let the Forum know when I get the engine started.

I can't remember when I last started the engine, it was at least 18 months ago, possibly longer.

Electrically nothing has been altered, the car has electronic ignition, and plug 6 produced a very good spark.
Mechanically nothing has been touched, so I have to assume the valve timing is unaltered.
So, although there is fresh fuel in both tanks, I'm forced to conclude there is a fuel problem within the carburettors. I will start with the fuel bowls as you suggest.

Regards, Richard

[NigelW]

Might be worth checking the float valves are working and allowing fuel into the float bowls as if the car has stood around a while these valves get stuck closed .

[NigelW]

Another thing to check, are the fuel pumps working? i.e. ticking when powered as the points get stuck with lack of use. I had trouble with one of mine this morning and had to give it a light tap with a screwdriver handle to coax it back to life. I recently had this with my XJ that hasn't moved for months.

[John Quilter]

If it fires once or twice and then throws the starter out of engagement I would think maybe the AED is not working. I would tap it a few times with the wooden handle of a hammer and see if maybe it will free up the internal valve which may have stuck closed due to old fuel residue. Just a shade tree mechanic test with not much to loose. Also test if the pistons in the carbs are free. Use the piston lifting pin on the side of the carb body and see if they fall back to the bottom with a clink.

[JCS]

Richard

The S type twin carburetter set up makes it easy to determine if fuel is reaching the carburetters. If you depress the tickler pin on the top of the front carburetter with the ignition ON you will be able to hear fuel flowing into that front chamber. This will also allow you to slightly flood the front carburetter without any dismantling of parts, most probably this will allow you to get the engine to fire.

You will notice Jaguar skimped having S.U place a tickler pin on the rear carb. Although you can convert the rear carburetter float chamber lid and fit a tickler pin, or fit a new converted lid, (note the lids are handed)

It is advantageous to convert the rear lid, as you can use the pins to temporarily flood both carburetters.

This small and easy modification will:-

Allow you to prove existence of fuel in each chamber

To enrich both carbs for a really cold start when the AEC auto choke may be purposely set weak.

Allow you to judge if the floats are actually floating and not sunk.

Allow you to test the pumps.

All without any dismantling of parts.

Note that the enrichment device is an Auxiliary Enrichment Carburetter (AEC) and not an Automatic Enrichment Device (AED), the latter is a very different animal.

Norman

[Glyn Ruck]

We are playing semantics gentleman. The tickler method does not necessarily achieve a start or stable running if sound long layup servicing is not done.
Best practice is to start & drive the vehicle periodically.

[Treetrimmer]

A big thank you to all those who have posted ideas and tips. It's heart-warming and helpful to receive to lots of constructive advice.

Now for the red face bit!

My first point of call was the A.E.D., and also it's Otter switch. The Otter switch tested fine ( the terminal was connected to earth, via the switch, correct for a cold engine) but nothing happened at the A.E.D. when the ignition was switched on and off. Tracing the wiring through revealed the Distributor earth wire connected to the Otter switch, and the Green/Black wire from the A.E.D. lurking unconnected in the engine bay!

However, we had by then begun investigating the fuel bowl chambers on each carburettor, and any re-assembly without fresh gaskets and fibre washers would only invite petrol leaks, plus there was already a fuel leak somewhere on the A.E.D.
So, I think the original problem was the inadvertent incorrect wiring connection. Incidentally, when correctly connected, it is easy to feel and hear the A.E.D. solenoid working when the ignition is flicked on and off.

Investigation of the fuel bowls revealed a missing "filter spring" in the front carb, and quite a bit of crud in the rear carb., so I think a good clean up is a worthwhile step. I have now ordered two gasket sets, plus gaskets for the A.E.D., plus a replacement filter spring, plus an S.U. manual, all from Burlen.

While I wait for the parcel to arrive, there is plenty of cleaning/polishing to be done.

So, thank you again to all those who have responded, but I'm now sure the original problem was down to careless reconnection of wires which were dislodged during other works.
I'll let you know when it is all running.

Regards, Richard

[Glyn Ruck]

Excellent news. So the green & black wire was off of the otter switch. Cleanup and gasket replacement is fine as is ensuring all parts present. No red face required. We have all made mistakes.

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