leaking gas while engine running

[n/a]

Hi

I pulled my 1969 280 SL out of the garage to prep it for the season, and I could smell raw gas. I went back to the garage and there was a puddle of raw gas. I had my wife start the car so I could see where the gas was coming from. It was coming out of something that was attached to the intake manifold. The gas was pouring out of a hole that was tapped for threads.

I took my trusty high powered falshlight, and found a small screw and washer lying beside this leaking area. I screwed the screw in, (it went in fine) and tightened it a little, restarted the car and no more gas leak.

Now, for my questions. First, what it this contraption that is mounted on the end of the intake manifold right beside the bolts that come through the chassis to secure my passenger side shock absorber.
Second, now that I have stopped the leak, is that it? What is this for? Is it some kind of adjustemnt screw? If so, is there a spring or something I should be looking for? Or by putting the screw back problem is solved? I havent taken it out for a ride yet until someone with more knowledge than I have can review this and advise.

Many Thanks

Lowleadman.

[Jonny B]

The device on the side of the intake runner is the cold start valve. It's pupose is to provide an initial shot of gasoline to get a cold engine running. There are a large number of posts on the forum relating to this device, so I would recommend you use the search function to find them. There may be some questions answered regarding this item that you might not even have thought to ask. They are also prone to internal leakage, and there are checks and procedures mentioned on how to deal with those.

Jonny B
1967 250SL Auto

[George Davis]

The cold start valve (CSV) is a popular topic indeed, and yours is leaking.  The screw you replaced is a test plug for checking CSV leakage.  No gas should come out of the hole if the CSV is sealing properly; if gas pours out, you CSV is leaking quite a lot, which means it's spraying extra fuel into the intake all the time.  It's a simple device that is often quite easy to repair, and as Jonny suggested, you can learn a lot by doing a search.

George Davis
'69 280 SL Euro manual

[n/a]

Thanks

Is driving with a bad CSV dangerous? I have noidea how long I have had this condition.

Thanks

Lowleadman

[George Davis]

I don't think it's dangerous as in explosive, but excess fuel can wash the oil off the cylinder walls and increase the wear rate.

George Davis
'69 280 SL Euro manual

[rwmastel]

I've read just about every post on this forum since it was started and with all the CSV discussions I don't recall anyone talking about the test plug.  Is this on all Pagodas or did the CSV housing change over time?  Where exactly is the test plug?  Anyone have a picture?

Thanks,

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[J. Huber]

Hello Rodd.

I am almost 100 percent sure that all the Cold Start Valves on 113s are the same. I base this on many discussions across the boards, so to speak.

There should be a small 7mm (if I remember the size correctly) screw on the side. To test the cold start valve, you remove this screw -- turn on the ignition to where fuel pump starts working (not to cranking)... Rag in hand, watch this hole for a couple minutes. If it leaks profusely you have CSV issues. If no noticeable fuel coming out, its likely ok.

Also, remember this is only one part of the testing of cold start issues...

PS I do recall stories of a leaking CSV having pretty bad effects on cars -- I would address it sooner than later.

James
63 230SL

[Cees Klumper]

Here's a photo - the screw in question is clearly visible:

Download Attachment: DSC00349.JPG
60.74 KB

I did not know that this screw is for checking whether the thing leaks. I will check mine.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[hands_aus]

This was discussed on the Yahoo site.

It was also recommend to have a fire extinguisher nearby.

The recommended leak rate is no more than 3 drops per minute.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[rwmastel]

Thanks everyone, that's great info.  I will check mine this weekend.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420