starting problem

[Melburnian]

Hi group,
 I have a 1964 230sl manual.
It recently has become very difficult to start.
It needs to be cranked many times before it will fire, if at all, but then it runs perfectly -idles smoothly, revs nicely, with no hint of fuel starvation .
This starting problem is not just a cold start issue. Its also difficult to start after going for a run.
I would appreciate any suggestions for where to start looking for this fault..thankyou!

[Peter]

Typically a CSV issue, I suggest you read the “Engine Starting Aid” which is part of the technical manual on this forum.

Peter

[glcg123]

There is a fuel enrichment solenoid at the back of the injection pump. It moves the rack to enrich the fuel mixture for cold and hot start scenarios. You can check it with a tester to see if it functions when you try to start the car. It will always be energized briefly while starting. It could be a faulty relay. The Tech Manual will be the best place to learn about it.

George
1965 230SL - 4 speed

[ja17]

With your early W113 you will need to identify which starting aid system your engine has first. It will either be version II or Version III. The starting devices are similar but their function is different with these two systems. The version II is unique in that it uses a "time switch" sensor along with a "thermo time switch" sensor in the system. All later systems did not use the "time switch". Identify your system and we can move forward. Most likely one of the electric relays that activate one of the two starting devices (cold start valve or injection pump solenoid) is not working.

[Melburnian]

Thanks Joe,
I inspected the cold start valve and found that a previous owner had blocked the jets with glue! ..why I dont know.
I managed to source some replacement jets and ,now fitted, the car is starting correctly. What I dont understand is why the car started normally for over a year with these jets blocked off and then became troublesome. A mystery but at least its working now.