engine falters when mixture screw tool is in place

[Norton47]

I was attempting to set the mixture on the carbs of the 6. When I place the mixture screw tool in place the engine slows way down and will some times die. Is this normal?
The cards are marked 175-CD2 and have temp compensation.
The engine seems to be running rich. It is also hard to start when hot, but starts easily when cold. I thought I saw some earlier posts on this but cannot find now. I keep listening as I lift the air valve for the speed up and return to idle or for it to run rougher,seems like no matter the adjustment if the air valve is held up it runs rough.
I have checked the diaphams for leaks they seem ok, I sprayed all around the outside when running with carb cleaner, especially at the throttle shaft no change to engine speed, also sprayed at all hoses, again no change. PO did install Grose-Jet No. EZ 401.
I also do not see this 175 CD-2 number in the Haynes book. It has CD DDS and CD-2S, these have no temp compensation and the book has a CD-2SE with temp comp. All seem to have about the same tuning instructions except the last have a very restricted range for mixture adjustment.
Any help or suggestions
Thanks /ubbthreads/images/graemlins/confused.gif

 

[DougF]

As far as the car stalling when you are trying to use the adjusting tool, that is normal. The piston is suspended from the diaphragm and when you push on the piston, it will alter your idle.
Were you able to insert the tool into the piston? My old '74 had non-adjustable needles from the factory. One of the first things I did was to install older adjustable carbs.
Air leaks would cause the carbs to run leaner. The only things I can suggest are: if these are nonadjustable carbs, you can try new needles. If you are not concerned with originality, get some older units. It will eliminate a lot of headaches.

 

[Norton47]

Re: engine falters when mixture screw tool is in p

Thanks
Duh, your explanation on the tool makes perfect sense. Should be able to figure that one out.
I also backed up and checked the timing. I had already set the valves but not checked the timing. Silly me.
It was set 16 degrees BTC. I adjusted to 4 degrees ATDC with the vacuum line on. I then checked the carbs and everything seemed to work much better. I have it at approx 800 RPM idle, when the air valve was lifted it ran faster and smoother, I turned it anti clockwise and it seems to now stay a constant speed when the air valve is lifted. The idle does not seem to hunt and it starts much easier when hot. It also seems to rev easier. It feels more lively. I will drive it to work tomorrow and check the plugs.
Why are there to clamps on the distributor? One is on the plate to the block, the other is a clamping bolt arrangement?
Also the tach cable seems to rest against the top of the fuel pump, when adjusting it seemed to want to push the distributor back due to striking on the fuel pump.
Is this common?
Thanks

 

[Guest]

Re: engine falters when mixture screw tool is in p

[ QUOTE ]

Why are there to clamps on the distributor? One is on the plate to the block, the other is a clamping bolt arrangement?
Also the tach cable seems to rest against the top of the fuel pump, when adjusting it seemed to want to push the distributor back due to striking on the fuel pump.
Is this common?
Thanks

[/ QUOTE ]

One plate should be to bolt the distributor to the block, the other to allow the timing to be changed by rotation of the body of the dizzy. I run my 6 on centrifugal advance and have the vacumm permanently disconnected. 8 degrees BTDC at 1000rpm. And yes the tach cable often will rub atop the fuel pump. Not a whole lot can be done about that, depending on where your timing is set.


Bill

 

[DougF]

Re: engine falters when mixture screw tool is in p

If you haven't already, you should balance the carbs.

 

[Norton47]

Re: engine falters when mixture screw tool is in p

Thanks
I have balanced the carbs. So an update.
I now have the car timed at 4 deg ATDC when the vac. advance is connected. The valves have all been adjusted. The carbs have been balanced using a unisyn. The mixture was then set and the lifting of the air valves seem to indicate slight to no increase in RPM when lifted a 1/16th".
After driving about 110 miles it used 6.2 gals, mixed highway and city driving. I was getting about 2O mpg. So maybe a little rich yet. I did not get a plug check done as the outside of master cylinder was wet with fluid, so I started looking into that.
Question, lots of information about moving the mixture screw one flat or such when setting, how do the newer mixture screws compare. Is on flat = to a 1/4 turn of the hex wrench?
Thanks