Misfire- intermittent!

[davidmuir]

Hi folks,
Out in 1967 850 today. Starts and revs cleanly but on road there is a 'stumbling' misfire occasionally. Stop and car again revs cleanly. (electric fuel pump under subframe-connections good) Tightened spade connections to coil (slightly loose) Checked engine earth- good continuity. Checked float height.Still misfiring.
Recently added 2 gallons E5 to tank(5 gallon one).............could it be older petrol already in tank? does it go off that quickly?
Mystifying!

[floormanager]

You running points? I had a misfire that flumuexed me with a new engine - the points were new and after ~250 miles, the point gap had closed up (heel wearing in) and it would not rev under load.

Another misfire I had was the rivet holding the spades on the coil relaxing, causing a poor connection - fun to find that one!

[360gts]

Check the connection on the distributor.....loose spade connector will also cause a misfire

[davidmuir]

Wire to distributor -tight.
But, points burnt although only tiny mileage.......we'll see tomorrow!

[minibitz]

Burt points = failed condenser.

Change points and condenser and you should be good to go again.

Although newish they just don't make things like they used to!

Other guys on this forum will more than likely suggest a source for better quality components.

[Catmint]

Burt points = failed condenser.

Change points and condenser and you should be good to go again.

Although newish they just don't make things like they used to!

Other guys on this forum will more than likely suggest a source for better quality components.

The Distributer Doctor https://www.distributordoctor.com/

Other thing to check is the insulation on the little cloth covered wire is in good condition

[davidmuir]

checked condenser using multimeter- seems good!
Will get a couple from Distributor Doctor just in case!

[Rolandino]

Check the coil, is it getting hot ?

[Exminiman]

Condenser problem can be intermittent, modern ones are crap.....read this and your be amazed any of the condensers actually work....at all

https://nonlintec.com/sprite/cap_failure/

[floormanager]

I only buy condensors from Distributor Doctor. Had one fail from a mini supplier after 4 miles.

[68&86auto]

Check that the condenser and it's connection aren't loose. If it's loosely mounted it will cause issues.

[Sixty2B]

I only buy condensors from Distributor Doctor. Had one fail from a mini supplier after 4 miles.

x2 for the Distributor Doctor.
Superb quality points, condenser and rotor arms.