yes the idle screw is been adjusted that was a different problem all toghther it wouldnt go down revs at certain point even if u took out screw then i figured there a adjustment of cable inside the car above speed!

thanks!

Is the idle stop screw backed off? The screw
To the left if idle mix screw

i put in all new gaskets on the carby in the rebuild.

thanks!

a friend of mine had the same sort of problem and found it was the bottom carby gasket. he replaced it and all is sweet.

yer its okay not bad just wanted to get rid of it might readjust the point again its like 48 degrees might adjust to 52 deg

Have a look at the idle screw tip, and the seat (part of the carb body) which the tip sits in, either might damaged. The shape of the tip corresponds to the seat that it sits within, if the tip is damaged it will not seat or seal properly (or do it's job). Sometimes people screw them in so tight that they damage the seat so getting a precise mix is difficult or impossible.

Other than that not sure what else it could be. 50rpm fluctuation is bearable though? Until you can fix the issue.

yer thats what i thought its supposed to do but mine does absolutely nothing fully leaned runs same as fully rich!

if you turn the idle mixture all the way in, the idle mixture is fully leaned.

you should expect engine speed drop if you turn in or turn out. i think, you shouldn't be able to idle if your mixture screw is turned all the way in.

http://datsun1200.com/modules/mediawiki/index.php?title=Tune-up

"Adjust carburetor at full operating temperature. Verify choke is fully open before adjusting

1971-1972 manual . : 750 best idle, then lean to 700 rpm
1971-1972 automatic: 780 best idle, then lean to 750 rpm "

o ok thanks one more question is the idle mixture screw ment to do anything to revs because when engine is on i can screw it in fully or out and it does nothing??

thanks!