1976 450sl what is throttle valve adjustment?

[jtdurett]

Hello,
I am replacing the 8 rubber spacers between the intake manifold and head and since I will have access to the throttle valve I would like to check it's adjustment. Can anyone tell me how to check this and what is the setting for the stop screw?

A side note: if you have replaced these rubber spacers before - about how long does this take?

Thanks in advance, Jerry.

[250 Coupe]

I have not done the spacers yet but am sure mine leak.

The only reference I can find for the throttle adjustment is job 30-300 at http://handbook.w116.org/ Before someone points it out, Yes I am aware that the 450SL is not the same chassis but job 30-300 is for the 4.5 in both 107 and 116 chassis.

To find job 30-300, I clicked the "open service manual library" link and picked 1976 450SEL since the year and engine match.

I then picked "Engine manual" and clicked next till I got to main function group 30.

You will find everything else you need to know for changing out the spacers here also.

Michael

[230/8]

The stop screw on the throttle valve should be a one time adjustment that sets the relationship between the throttle position switch and the throttle. You do not need to periodically adjust this unless someone has messed with the adjustment or replaced the switch without re-adjusting the screw. You do not set idle speed with this screw.

[Lexxani]

Originally Posted by 230/8

The stop screw on the throttle valve should be a one time adjustment that sets the relationship between the throttle position switch and the throttle. You do not need to periodically adjust this unless someone has messed with the adjustment or replaced the switch without re-adjusting the screw. You do not set idle speed with this screw.

It should not be in need of adjustment. A visual inspection should be sufficient. If with no load on the throttle cable the valve should be closed.

When you remove your Fuel Injection, look at the valve, if its all the way closed, you should be within tolerances. I have yet to hear of one of these valves coming out of adjustment from the factory spec (unless messed with by someone). These are my observations from working under the hood of my '78 M117.985, which is your engine model.

[jtdurett]

Thank you to everyone who replied! This information is very helpful.
Jerry

[halw540]

"A side note: if you have replaced these rubber spacers before - about how long does this take?"

Jerry, plan on between 1 to 2 full days to replace the manifold seals depending on how fast you work. I suggest you also replace all the injector seals and fuel hoses, along with all vacuum lines while you are going. If I were doing it again I would plan on having the injectors cleaned professionally while I had things apart - makes a big difference. While I am helping you spend your money it is a good time to replace water hoses with everything apart and easily accessible. A crows foot wrench will help in getting the brake vacuum booster line loose from the manifold by the firewall. Also there is a banjo vacuum fitting low on the manifold's passenger side, by the firewall, servicing the tranny modulator and vacuum switches that is a real pain to remove/install - watch out and don't loose it's copper seal washers.

Hope this helps - Hal

[250 Coupe]

Everything Hal says plus;
Replace the big vacuum hoses from the throttle body through the aux air valve and under the fuel distributor. Mine were brittle and leaked like crazy.

Scroll down to page three here and think about replacing items 1, 4 and 9.

Michael

[jtdurett]

Thanks for the additional replies. I changed out the 8 rings and reassembled everything. It was straight forward just a lot of time as mentioned. The advice about hose etc. was well taken too.
Thanks again, Jerry.