Issues with Adjusting Fuel Mixture

[DienstXIV]

Hi Everyone,

I just got done fixing a bunch of vacuum leaks on my CIS 1975 Porsche 911S but now my car seems to be running worse. I think the engine might be running too rich since I was reading that people tend to richen up the mixture to compensate for vacuum leaks.

I followed the CIS tuning section on how to adjust the fuel mixture but my adjustment screw will not turn. I put quite a bit of force on it but I am afraid I could break sometime if I really give it some muscle. I put some DW40 in there but still nothing. Does anyone know if I could break something expensive if I apply too much torque? Has anyone else had this issue as well? I really don't want to have to take the intake system off the motor again!

Thanks in advance for the help!
Cheers!
Alex

[Dr J]

Are you sure the allen key is entering the adjustment screw? If you haven’t done it before it could take some practice. Worst case is that you round off the adjustment screw and have to pull the air metering plate and force the screw off in a bench. Keep trying some penetrant. If you damage the screw it would not be expensive in terms of parts but definitely a pain in terms of labor.

[john walker's workshop]

I find a tight one occasionally. Never stripped one using more force.

[DienstXIV]

Originally Posted by Dr J

Are you sure the allen key is entering the adjustment screw? If you haven’t done it before it could take some practice. Worst case is that you round off the adjustment screw and have to pull the air metering plate and force the screw off in a bench. Keep trying some penetrant. If you damage the screw it would not be expensive in terms of parts but definitely a pain in terms of labor.

I am pretty sure it's entering the adjustment screw because when I go to pull the allen key out there is some resistance like I am pulling the allen key out of a tight fitting hole. Also since I cannot rotate the allen key it's gotta be in place right?

[john walker's workshop]

A longer 90 degree angle on the tool helps.

[proporsche]

you can order from Stahlville company the correct tool like this
Ivan

[boyt911sc]

Place a piece of rag in the air box directly under the access hole. Push the lever up and spray some penetrating oil through the hole. And saturate the fuel mixture screw with penetration oil and allow to sit for a while.

If you raise the arm or lever of the sensor plate, the top of fuel mixture screw could be seen partially. See picture below. Spray some penetrating oil and allow to soak.


Make sure you got the Allen wrench key engaged properly and turn it left and right. There is nothing to worry about the breaking something. It is built well and strong as a tank.


Tony

[DienstXIV]

Thanks everyone I was able to adjust the mixture it's still rather hard to turn but at least now with a pliers I was able to adjust it and I got the car running a little better. My next question is where is the best place to get an exhaust gas analyzer? Would anyone have one in the Chattanooga area I could borrow? The cheapest one that I can find is $250 on Amazon.

[proporsche]

don`t waste you buck..try to find a friendly smog station nearby who would let you check it

ivan