Tuning Warm engine won’t start

[UncleP]

Greetings everyone,
I just finished a complete restoration of a 1959 Jolly 500N.
Everything in the engine is new or rebuilt. Also have a new fuel tank and fuel lines and a new ignition system with Pertronix instead of points.
The engine starts fine with the choke when cold and the car runs and drives well. We did have some issues with the pilot jet getting clogged with small debris, so I took the carb apart again and cleaned all the passages with brushes and reamers (had some corrosion) and added a fuel filter between the fuel pump and carb.
The car starts fine when cold but will not start after it’s warm. I did manage to roll it down a hill and bump-start it once but the starter won’t quite manage to start it.
HELP!

 

[the hobbler]

Greetings everyone,
I just finished a complete restoration of a 1959 Jolly 500N.
Everything in the engine is new or rebuilt. Also have a new fuel tank and fuel lines and a new ignition system with Pertronix instead of points.
The engine starts fine with the choke when cold and the car runs and drives well. We did have some issues with the pilot jet getting clogged with small debris, so I took the carb apart again and cleaned all the passages with brushes and reamers (had some corrosion) and added a fuel filter between the fuel pump and carb.
The car starts fine when cold but will not start after it’s warm. I did manage to roll it down a hill and bump-start it once but the starter won’t quite manage to start it.
HELP!

For a start, REMOVE that filter between the pump and the carburettor---it will be having absolutely no effect on the poor hot start problem and is a fire risk. I would almost put money on the fact that the filter is a plastic-bodied filter, and having that almost over an electrical item (the dynamo) with 2 'pipe-to'filter' joints is a recipe for leaks and a engine bay fire. You already have a filter on the end of the tank-unit, possibly one in the top of the fuel-pump and also one in the top of the carb---YOU DO NOT NEED A 4th!
You say that it won't start when hot using the starter, but it WILL start if you "bump-start" it---is that because the starter won't crank it over when the engine (and therefore also the starter,) is hot? Any further 'situation' information would be appreciated.

 

[USA Paul]

The starter cranks when hot, it just does not quite start the car. I bump started it in desperation when it was hot and it worked.

 

[giardini]

Valves clearances ? Too tight, and the starter won't start a hot engine, but a bump-start will, as it spins the engine a bit faster.

 

[the hobbler]

Valves clearances ? Too tight, and the starter won't start a hot engine, but a bump-start will, as it spins the engine a bit faster.

Thank you for that extra piece of information regarding "non-hot-start". I would agree with "Giardini" with regard to valve adjustment ('lash' to you on the other side of the 'big-pond'). For some unknown reason, the 500 is prone to valve-clearances closing. Even if that is not the cause, it will be something that can be ticked off the "possible cause" list. Valve clearances on the 500D/F are 6thou (0,15mm) COLD

 

[USA Paul]

Thanks guys , I will look at those items you mentioned.