Lean running? After csv repair

[Minerva]

Hi just almost ready to put a 230sl out on the road after a major rebuild,  I had quite a leak from the csv, lapped in a new plunger in it and now no leak.
Only thing now is I seem.to be running very lean, she'll start ok, csv shuts off, runs ok at idle for about 3 or 4 minutes and then starts to falter.
I'm presuming that as the csv was leaking previously, this was enriching the mixture and keeping her going, what I could do with knowing is there any base point for the mixture thumb screw on the rear of the injection pump? Does it have a stop or how much richer will each click make it.
Thanks Keith

[teahead]

Run a vacuum gauge.

When it falters, what's the idle speed?

Yes, try clicking to the right (clockwise) a few times (while engine is stopped) and try again.  If it's really low in vacuum, start turning the air screw clockwise until vacuum goes up.

[Minerva]

Idles about 950 from cold, t seemed more before the csv was repaired but hard to say as neither the rev counter nor the exhaust were fitted.
Out of interest, what's the reason for clicking the adjuster when the engines not running?

[teahead]

I think you can ruin your FIP if it's running while you mess w/that thumbscrew.

[Benz Dr.]

I think you can ruin your FIP if it's running while you mess w/that thumbscrew.

It does a pretty nice job of chewing up your fingers too!

 You want everything stationary while you do those adjustments so you can keep track of how many clicks you turn the knob. 6 clicks equals one full turn and from not running at hot idle to where it will stay running is at least a full turn or more on most engines.
 The further you have to push the knob in before it engages the richer the idle mixture. If you can barely push the knob in, it's set really lean. This can all be changed relative to the setting on the BC. If it's a bit lean or rich it can really change the base settings at idle. The mixture knob is only for fine tuning and the IP is very sensitive to any adjustments.

[Minerva]

Thanks folks I'll report back.

[Naj ✝︎]

Hi,
You also need to ensure that the air from the warm up circuit (the little air filter on the injection pump) is completely shut off after warm up.
If not, extra air from there may be leaning out your mixture.

naj

[Minerva]

Some further info, I've enriched the idle as per Dan's advice but no difference, I've taken the small air filter at the injection pump off and blocked it with a bolt and she still cuts out after the same time period.
I've plenty of fuel at the injection pump and plenty in the return. When she cuts out it's due to a lack of fuel as there's nothing coming out of the injection pump, and won't till she cools down. To restart when hot she needs about half throttle to get the fuel to flow again and will continue to run only with throttle.
It looks like the leaking csv was keeping her running at idle speeds, so what could knock out the injection pump when warm?
Thanks in advance!

[Shvegel]

3 or 4 minutes from a cold start should still be in the range of the warm up regulator.  If it runs OK warm then you should be looking at adjusting the warm up regulator.

[Benz Dr.]

Turn your BC out about a half turn. Mark it first before you start turning so you won't loose where you began.

Once you figure out where it will run properly then you will need to find some shims to adjust to the same place. It sounds hard to do but it really isn't. Once you have it running OK then you should be able to fine tune with your idle mixture knob.

If the air isn't shutting off on the WRD you would likely have a rich mixture condition. The small amount of air going through the little air filter will not compensate for this.

[Minerva]

Dan I'm scratching my head what's the BC you refer to?
Keith

[Cees Klumper]

Barometric Compensator, the larger round 'can' that sits horizontally on top of the fuel injection pump.

[Minerva]

Thanks Dan, increasing the barometric compensator did the truck, had to back it out quite a bit bit idling great now, thanks all for your input!
Keith.

[jeffc280sl]

That's great news.  About 3/4 of the way down this page

https://www.sl113.org/wiki/Engine/AltitudeCompensator

you will see a picture of my failed BC.   

A failed BC will exhibit a fully deployed pin which will greatly lean the air fuel mixture. The failure mode for this device is a loss of vacuum seal inside the bellows. As the bellows loses vacuum there is nothing left to oppose the force of the spring inside the bellows.