Setting up Carbs/slow idle too fast

[Rick60]

Hi, had my carbs (HD8) setted up yesterday and was wondering why I couldn't get the engine's idle speed below 800 RPM /ubbthreads/images/graemlins/confused.gif
Checked the float level and corrected it to the specifics given in the manual (7/16"). After taking off the suction chamber I could clearly see the throttles being completely closed. Then I set the mixture by screwing/unscrewing the jet adjusting screws (after initially setting them on the same height) so that when I lifted the pistons inside the suction chamber the engine speed would slightly increase and then fall back to the former rpms.
After these settings were done I tried to correct the slow idle speed. After having fully turned in the slow idle screws engine was still running at 800rpms. Choke was fully pushed in!
What does this symptom cause except of air leaks since the carbs have been rebuilt about 5,000 miles, but 12 years ago?
Is there a possibility of faulty diaphragms?
Any suggestions appreciated. Thanks

 

[tahoe healey]

Even though the know is all the way in , the choke may still be operating. Be sure the fast idle screws are away from the little plate (equally). Be sure there is slack in the cable at the carbs. I feel a smooth, even running 800 rpm is very good. It may drop after a few miles of driving when things get hot. You may also want to check the rpms with an auxillary tach. The car tach may be off a little. I am at 6240 feet and the idle is different up here than it is at sea level so I'm constantly changing the idle when I'm off the mountain. Faulty diaphrams?

 

[Rick60]

Fast idle screws are away from plate and rpms were checked with auxillary tach. Maybe there is not enough slack in the cables. Will check and report back. Thanks

 

[Rick60]

Oh, and I forgot to mention, I meant the diaphragm holding the jet. Maybe this is faulty due to it's age (12 years).

 

[Rick60]

Checked the cables yesterday and they are slack with choke fully pushed in. Fast idle screws have clearance of about 1mm. Engine still revving at about 800 rpm when hot with choke pushed in and slow idle screws fully turned in.

Any other suggestions?

 

[Keoke]

HI Rick 60, An idle speed of 800 rpm hot would not bother me too much if all other adjustments responded correctly. However, the carbs may be sucking air around worn bearings on the throttle shaft or the gland washers at the ends of the shafts may be missing or have dried out and are leaking.The Tick over screws also have rubber sealing washers that may be leaking and it would not hurt to also verify that the Timing is correct and steady at Idle-Regards Keoke