2.25 petrol not running well

[alex1987]

Hello everyone!

 I recently took my series 2 out of hibernation and she just isn't running quite right.
Battery charged, fresh E5 petrol, primed her up and she started easily and and is fine on idle.
When she gets hot, she has started back firing and cuts out at alot of junctions. She starts up quickly luckily and carries on until the next time.
I rarely use her over winter so this has been my routine for the last few years but she has always ran fine until this year.
Does anyone have any ideas what it could be or checks I could do please. I'm a bit of a novice to ge honest but do my best!
Thank you!

P.S she has a Weber carb.

[nathanglasgow]

Check the easy stuff first eg points,rotor arm, condenser, coil.

[Adam1958]

The back firing and cutting out when hot hints at a few things, but a bit more info might be good. Does the backfiring happen with the throttle wide open under load, or off throttle up to a junction on over run.
When the poor running condition occurs, does the application of choke improve or worsen it?

Next, Tom recently had a low power, poor running condition that we chased around in a circle for a morning, only to realise the clamp holding the distributor had loosened enough that the distributor had rotated a bit giving a much retarded ignition... similar symptoms to what you have. A very easy check and fix fortunately.

Good luck.

[alex1987]

Thank you for the advice. I will do some checks over the weekend.
The back fire happens on over run mostly. Unfortunately my choke cable has snapped and I have not replaced it yet so haven't been able to try applying it.

[Adam1958]

If it's a backfire on over run then do check all the obvious ignition bits, but that crackle off throttle is more often a symptom of running lean. It could be a blocked jet (which seems unlikely since it starts with no choke) it could also be a loose or cracked intake or exhaust manifold, that sometimes produces a lean crackle off throttle.

Let us know how you get on.

[Alan Drover]

With all that free backfiring you'd be the envy of the yoof in their electronically controlled junk. They obviously have to pay for a "backfiring programme."

[Countryview]

I had a backfire when going down hills on overrun a couple of weeks ago, I cleaned the oil breather cap, idle jet and the petrol sediment bowl which was full of debris, tightened the distributor cap clamps and touch wood haven't had it since so maybe worth a check

[alex1987]

I have had a quick look this evening, bit of a plonker as I didn't mention she has electronic ignition so no need to check points etc. The distributor was tight. About 30 seconds into the drive I had a few pop pops of backfiring on over run and she cut out when I stop at first couple of junctions. I drove around 20mins and she was fine, no back firing or cutting out. I stopped for around an hour. She started up no problem to come home. Again first few minutes of driving she was backfiring and cutting out. About 5 minutes into the drive she started to behave and was fine all the way home. At first I thought it was when she was hot but now seems to be at the beginning of the journey. I plan to drive her to work tomorrow which is 10miles so will see how she behaves then.

[Wittsend]

When you say you have electronic ignition - whose

Some cheapo Chinese kits aren't up to it 

Could you have a loose connector in the circuit ?

And do you have a Distributor Doctor's red rotor arm
Very important as the cheap pattern Lucas copies have a brass rivet that can short out internally and cause all sorts of ignition problems




You need one of these ...     

-expert

[alex1987]

It was from britpart so quite possibly a Chinese one.
It was a few years ago it was fitted so I can't really remember. I don't think the rotor arm is red. I'll have to look into getting better quality to rule it out.
Thank you.

[Alan Drover]

Try a Distributor Doctor rotor arm first. The cheap and nasty rubbish ones usually short out on the rivet holding the brass contact to the plastic. If that doesn't work you'll probably need a new ignition set up. The Doctor sells Pertronix, not cheap but well made and reliable, cheaper in the long run than 'orrible Chinese rubbish.

[Wittsend]

If you have a whole electronic dizzy then you need to dump it.

You need a genuine Lucas D25 unit. You can then "upgrade" to contactless ignition.
You can use either the PowerSparks, Petronix or Lumenition units.



Lumenition Ignition




Petronix 


With a base standard dizzy you can always convert back to contact points at the side of the road should the unit fail.

-25D

[alex1987]

Looks like I have the crap rotor arm! I'll be ordering a decent set up over the weekend.
Thank you very much for all your advice.

[alex1987]

Looks like I have the crap rotor arm! I'll be ordering a decent set up over the weekend.
Thank you very much for all your advice.

[Alan Drover]

Yes,it certainly looks like it. Be careful though because there are now cheap rubbish copies of the red ones about. Best get one from the Distributor Doctor. His are proper ones, same with his points, condensers and distributor caps.