She'd not be run for over 10 years, so there was the usual recommissioning, plus the clutch issue that had caused her to be laid-up.
The dual twin-choke DCOE Weber carbs has to be stripped, cleaned and rebuilt.
The engine-driven mechanical fuel pump was replaced with electric, so engine doesn't have to crank for ages if the carbs are empty.
A few other jobs came up, like replacing the engine mounts, which included a snapped stud, and the front calipers had seized, so there were distractions while I was scratching my head over the engine.
Initially she would fire up, with a few impressive backfires, and then die.
New plugs and HT leads fitted and a set of HT/Plug testers slotted in, so I could check what the ignition was doing.
- plug tester.jpg (21.66 KiB) Viewed 55 times
I wasn't convinced and, after a while, I discovered that the IGN output on the ignition switch was putting out less than 9 volts when in the Running position. It was fine in the Start position, so the ignition system was getting just under 12V while cranking, due to the starter load, and then even less when the key was released.
A new ignition switch was required, as the original isn't rebuildable though it obviously had a burnt/worn contact. Maybe it had grown some corrosion while parked-up.
With the new switch, the backfires were history, but I still couldn't get the engine to run for more than a few seconds before dying, regardless of how much I attempted to catch it on the throttle.
With the HT testers flashing away nicely, even while it was dying away, the issue obviously wasn't ignition related, was it?
Bad fuel?
The tank had been drained and the new pump used to flush the lines with the help of an extra inline filter.
However, a gravity tank of clean fuel, hung above the engine mad no difference.
The dual twin-choke carbs and the intake arrangement meant that there was virtually nothing else that was common to all four cylinders, that could go wrong on the fuelling side.
I had a spare ignition coil, so tried that, with not difference in symptoms or flashy tester outputs.
The HT cap looked perfect, as did the points, which were checked for gap and timing.
With only one thing left, I replaced the condenser on the side of the distributor, that's meant to just stop the points arcing/burning.
This was awkward, as the only replaced I could source was a different mounting, but was got there.
Fired the engine up to confirm that I hadn't broken anything while doing that job, and she sat there ticking over!
She was running cleanly, responsive to throttle, left running until fully up-to-temperature and then switched off.
At no time in this whole saga did the output from those flashy testers look any different
Had I not have used them, I would have focused on the ignition system from the off, as that's what my gut was saying, but the testers said different.
The moral of this story is...
If the testers don't flash, you haven't got HT output.
If the testers do flash, you do have some HT output but it might not be enough to run the engine.
