I have a 1972 500 L with a 126 650cc Engine. I timed the 123 ignition using "0". I'm having issues starting the engine. So we pushed started the engine and it was working great.After about 15-20 minutes it starts to loose power gradually and eventually dies on its own. Now it will not start at all. I have renewed sparkplugs. and installed the 123 ignition. Any idea's?

Hi it's Wayne here (Jens other half) when i fitted that unit to Jens 500 i did it as per the instructions and it wouldn't run properly, so i slowly turned it forwards and backwards until the engine sounded happy , then road tested it for fine tuning making sure there was no pinking (detonation),
Hope this helps
Wayne

She runs great it sounds better than ever. But starting it is the issue. I have adjusted the idle screw on the carb and nothing.

Any other ideas? This is killing me.

The timing may still be too retarded or too advanced, which means it would run but would be hard to start.

If when your cranking it it doesnt turn over freely and it sounds like the engine is stopping as it comes up on compression, the timing is too far advanced.

Otherwise it may be too far retarded, try making small adjustments and try it.

Also if youve had to adjust the idle down this could point to it been too far advanced also.

Let us know !:bang:

Thanks. I reset the timing and it starts but after a few mins it begins to die again. Once the engine is warmed up its hard to start. I need to wait till it cools down. Any suggestions?

Dos2 said:

Thanks. I reset the timing and it starts but after a few mins it begins to die again. Once the engine is warmed up its hard to start. I need to wait till it cools down. Any suggestions?

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Hello and welcome to the forum.

This unfortunately seems to be a common phenomenon with the classic 500, and if you do a search of this section you will find several threads all in the same vein.

Causes can sometimes be very difficult to track down, but as you have fitted the 123 Unit which cured this problem with our car, this kinda points possibly to a fuel related problem.

One thing that springs to mind is the carburettor flange face which may be distorting when it gets hot and allowing air leakage.

This results in a weakened mixture which means the engine will probably run just fine, but will then not restart whilst it is hot.

When the engine cools, the leak re-seals itself.

Just a thought.

How do the plugs look? Are they the correct colour around the electrodes? They should be a kind of grey colour. If they are white, this would also point to a possible cause.

Let us know how you get on.

Finally! I adjusted the valve adjusting screw and now it runs fine!

WOOOOOOOHOOOOOOOO ! Happy motoring !!!