Wet Spark Plugs

I have a 168 Series 1.5 OTS that has the three SU carburetors.

The car has been running very well for several years, but in preparation for a long trip I decided to tune it up with new points, plugs, etc. The tune up was done at a local old Jaguar specialist. The car ran very well after the tune up for about 50 miles worth of trips over the next few days. When I was letting it idle a few days after the tune up to let it warm up it started to rough very rough, then quit. I tried to restart it by changing distributor cap and rotor arm that I had hanging around. I eventually had it flat bedded back to the repair shop to fix the problem. The repair shop has reported that the plugs were very wet and not sparking. No further work is being done until new ignition parts and coil turn up from SNG Barrett. The shop did not report if spark was being delivered to the plugs.

My question is, what would cause the flooding or wetness of the spark plugs? I have been told that SUs do not have an accelerator pump, so with my continuous cranking of the engine with it not firing, could this cause it to flood because of gases being drawn into the cylinders without firing?

I use Seaform in my gasoline and have a shutoff valve at the carburetors to run them dry every time I put the car away. I am hoping that there is no problem with the carburetors. When fiddling with it when trying to restart it I noticed that the wire to the points was frayed down to one strand, so this may have been the problem at first, but then the flooding may have prevented it from firing after I repaired the wire.

So, does anyone have any suggestions as to why a set of SU carburetors would flood?

Thank you

ok so i’m a bit baffled by you story, 1st, were the plugs wet from fuel or oil? you had a tune up by a local jag shop - car went well for 50 miles - then idling it ran rough - change dissy cap & rotor (shouldn’t have need that if tune up done correctly) flat bed towed - why does it need new ignition parts? that implies the workshop didn’t a proper job… i’d be asking were the plugs wet from fuel or oil…if fuel they would have been fairly dry by the time itt got back to the workshop…also i’d be asking “what was done to the carbs during tune up?” were you using a choke when cranking? (would cause flooding if no fire) sooooo…i’d be asking the question> why does the motor need new ignition system wen the car has been running well for several years & why weren’t these problems picked up during a tune up or if in deed a proper tune up was done…sounds like that workshop is a bit shonky

Sounds like you may have had a problem with one or more needle and seat (s) which control the fuel flow into the bowls, or alternatively a float has sunk or is sinking, or your choke is stuck open, or partially open, but frankly there’s really not enough details to diagnose the issue. Doesn’t sound like an ignition issue - usually that works or it doesn’t.

There can be a problem when you start with a dry float bowl, in that a needle can stick open in the seat, because the float assembly actually drops too far. That could be your problem - in fact I strongly suspect it is. There is no discussion about this in any Jaguar manual I’ve seen, but in the Weber material, which uses a similar needle, seat and float arrangement the maximum drop of the needle is specified, and can be adjusted. On some float bowl arrangements on E Types it is possible to control the total drop of the needle by adjusting a small tang on the lever that operates the needle when the float rises and falls.

Yes, the repair shop appears to be shoddy. That is why I am enquiring on this forum as opposed to simply allowing the shop to figure it out. The trouble is finding repair shops that work on these cars that are somewhat local, so I have to compromise.

And yes, the choke was on.

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Hey Rob. The first thing the mechanic would have done when you took the car back the shop is crank open the choke and attempt to start it. When it wouldn’t fire he’d take out the plugs for inspection, and they would have been wet with fuel. Ergo, no spark. You don’t mention if your ignition is stock points or electronic. If the former I’d suspect a failed condenser. Less likely the coil. The only electronic replacement I’m familiar with is Pertronix, as that’s what I have installed in my ‘68. Two local car buddies have the same, and both have experienced sudden failures after having left the ignition on without the engine running. Fries the optical sensor. In any event, I highly doubt the car needs extensive work to fix.

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Nick, Thank you for the reply. I concur with what you are saying and hope the mechanic arrives at the simple fix quickly and cheaply. I have regular ignition and have considered the Petronix or the 123 Ignition sold by SNG Barrett. Before I do this, I want a work around for making the tach work with an electronic ignition. My tach is not driven by the cam so the electronic ignition may cause issues. Could you please share with me if you had a problem with the tach and your electronic ignition, and if so, what was the work around. And what about your two local buddies. Thank you.

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My tach works fine with Petronix, can’t speak to the 123.

The 1968 Series 1.5 tach is as you know unique, Rob. It’s the only year with a 5500 rpm redline and no clock. It functions exactly the same as the Series 2 tach with the 5000 rpm redline (It’s also the only 4.2 litre tach with a 5500 redline. I’m all but certain the ‘68’s redline was a marketing ploy for the dominant US E-type market as some sort of salve for the reduced official horsepower of the twin stromberg smog setup - which Canadian delivery cars like yours and mine were spared.) But, yes, you’ll probably need to get your tach converted, though I understand some seem to work ok without modification. I have two Series 1.5 tachs and neither one would work with the Pertronix. I had one done up by Morris MIntz at West Valley Instruments in California - great job, quick turnaround and fair price.

One of the two here who had Pertronix failures has an E-type - a ‘69 Series 2 - and the other a ‘57 Corvette. I don’t know about the latter, but the Series 2 also required a tach conversion in order for the Pertronix to work. Again, you can’t turn the key to the “ON” position and leave it there without the engine running, as both gentlemen learned the hard way, unless you disconnect the wire from the coil to the dizzy first.

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My Pertronix distributor was truly “plug-and-play”; no modifications needed (Series II, 4.2L, February 1969 build date).

I always disconnect that wire when I’m doing something that requires the ignition to be on with the engine not running. i

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so boiled down–you say, it ran well for a long time, then a tune up that maybe it didn’t need–but ok…after which it started up ok, and ran 50 miles ok…but then at idle roughed up, died, and would not restart at all. The wet plugs may be a “red herring”…not what is wrong but CAUSED by the attempted starts that produced no start…so CAUSED by what failed after 50 miles of good running after a good start up…and probably a good start up and test run by the shop mechanic–: something failed–something that was likely installed: As to ignition that “works or doesn’t”…currenty it doesn’t. The problem was not intermittent–it quit and won’t restart. I would not suspect carbs nor float–but float check is easy enuf to do quickly–but it seems more to be ignition failure–some new parts are bad from the box–or soon to fail–condensors, electronics.: let the shop figure it out thru some of the routine tests…do easy things first, do checks of what was replaced first–not some brand new issue. The checks for spark or no spark are routine. I don’t recommend your running til out of fuel all the time. Cars sit with fuel all the time, often and for months–modern fuels don’t varnish as much as way back then–this is why you don’t hear about clogged fuel injectors as you did at first. Try to use non ethanol–but if you use the 10% then add a stabilizer and a little extra fuel cleaner like Techron or Gumout Regane-with PEA. Running lean often–can damage valve edges and seats and is not necessary.
Nick

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Hey Robert:

There’s a good chance it’s a failed condenser or possibly the distributor rotor - the quality of both are suspect aftermarket parts these days. If you still have the old ones try putting them back in and you might get your spark back. :slightly_smiling_face:

This is why I switched to electronic ignition several years ago - we just could not seem to get a reliable condenser that would last more than a week or 2 - so simple but so frustrating at the same time. Had a similar problem with a distributor rotor as well - went to the red rotor and problem fixed plus I now carry a spare in the car just in case. Chalk it up to the joys of running an antique automobile. When you get it sorted out it will once again be running well for several more years. Happy motoring! :sunglasses:

The same guy who manufactures the red rotor also sells high quality points and condensers. The Distribuitor Doctor.
No affiliation but strongly supported for old P&C guys like me.

Exactly, Marco. DD is located in the UK but on this side of the pond there’s Jeff at Advanced Distributors located in Minnesota who also supplies the red rotor arms (no affiliation but I do have one on my car and no issues unlike the prior carbon black cheapo version that caused a dead short to ground). I see Moss Motors carries them too and they’re now being clearly marked “AD” to avoid confusion with the counterfeiting that’s apparently going on - it seems there’s no end to it.
Distributor_Rotor_Red

Did somebody call for a doctor? Yes, I did - here’s what the Distributor Doctor has to say about the quality of rotor arms: Red rotor arms: The Original and Genuine Red Rotor Arm, Lucas part numbers 400051, 418726, 54422803, 43D, 45D, 59D, 400052, 418731, 425620 from Distributor Doctor

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My '68 tach has worked well with my Pertronix module from 20 years ago without any conversion. I did have a case a few years later where it did not work initially after I had to replace the section of white wire that loops through the back of the tach but after I played around with the loop portion where it passes thru the plastic block it started working again. Not really sure of the cause and what I did to really fix it though but has been working well for many years since.

David
68 E-type FHC

It really is a shame. Because of this and the other sub-standard parts sold I deal with Martin directly. He is a good guy and easy to talk with, he also carries many Lucas oem parts. I was able to purchase a set of oem Lucas distributor springs and an oem Lucas distributor cap with threaded wire hold downs.

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