Technical Not starting 500f

[Mark0474]

I know it’s been discussed to death but this is strange.
I ordered a new distributor cap and rotor, plugs and leads.
Changed them over for the new set and car won’t start.
Put original all back in and now car still won’t start. Before changing car ran and I wanted to do rotor and distributor as looked worn the spark seems very weak and as I said, can’t get it started.
Thanks for any help.

 

[smart51]

Like they say, you only need 3 things, the right fuel - air mixture, good compression and a well timed spark. If you've not changed the fuel or compression, something's happened to the spark.

In replacing the parts, could you have knocked the timing out?

Have you tried turning the engine over with the spark plugs out? Can you see them spark?

 

[Mark0474]

I haven’t touched the timing at all, I know get a backfire now and then.
Just to confirm, cylinder 1 is the one closest to the boot opening and that HT lead goes to no:1 on the cap.
I’ve checked fuses, there is a weak spark, I checked the gap is between 0.6/0.7mm.
I also haven’t touched the carb.
It’s very odd

 

[Toshi 975]

Try swapping over the plug leads

 

[Mark0474]

Try swapping over the plug leads

Tried that one.

 

[Goldnrust]

If the spark is visibly weak, then that seems the place to concentrate your efforts, especially as that where you’ve also been in making changes.

Check the points gap, check the resistance across the primary and secondary coil windings, make sure you’ve got a good 12v supply to the coil. If you’ve got a spare condenser, try that. They seem to be a common failure point on 500s.

 

[Mark0474]

Thank you. I’ll check those ideas out. Thanks

 

[dangfiat]

Interesting problem...

I'd have to assume that either the coil wire's come loose or the condensor is an issue

I'd look at:
1. Pull a plug and hold it next to the case while someone cranks... are you seeing a spark? Is it reasonably bright?
2. If not: check/replace condenser and check all the connections from the coil.
3. Try for spark again
4. if not, maybe coil?
5. Finally, it's possible you've knocked out the timing... but these motors are pretty tolerant to crummy timing (ask me how I know!)

I'd bet it's either the condenser or a loose connection that got knocked out while you were in there. It's a tight space...

Let us know what the fix is or if you're still having issues. It's good when we close these threads with a solution so others have something to learn from

Daniel

 

[Mark0474]

Hi

Ok, so I think it was a variety of things that caused my issue.
There was fault in the new distributor cap as well as one of the HT leads

The timing was just working and sparking in the points. They were working but just! I adjusted the points as best as I could as they need renewing, what are the chances that the new points I ordered were missing one of the points!!

I adjusted the timing, put the original distributor cap, rotor and HT leads back in and then it fired up without any hesitation.

I have decided to spend the money and go along the route of the electronic ignition from 123. My distributor has a lot of play in it, all directions and I think over time I might get the same issues as before.

It was still very strange that I hadn't messed with the timing at all before this started, simply removed the rotor, cap and leads, new plugs. The lesson for me is to literally change each item 1 by 1 and check the car starts.

Thank you all for your help and advice. Next is the installation of the electronic ignition and coil.