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Idle RPMs

Posted: Mon Jul 09, 2018 7:24 pm
by Jim Beam
1963B Coupe Normal; running Weber 40s with Bosch 050 distributor. Suddenly the idle speed reduced itself to about 300 RPMs. Motor quits at that RPM. Wondering is there is a relatively simple adjustment to be made to increase the idle speed to around 750 RPMs?

Re: Idle RPMs

Posted: Mon Jul 09, 2018 7:41 pm
by Dick Weiss
Each carb has an stop screw which adjusts the carb's idle RPM; For an balanced idle, you must use a Unisyn, or Sychronometer (gage).

Re: Idle RPMs

Posted: Mon Jul 09, 2018 8:11 pm
by Doug McDonnell
But if everything was fine with stable idle and you suddenly developed this then there is a reason to be found. Distributor plate was sticking for a long time and finally went back to base? Doubt it. Maybe a partially clogged idle jet? More history would help.

Re: Idle RPMs

Posted: Tue Jul 10, 2018 6:16 am
by Neil Bardsley

Re: Idle RPMs

Posted: Tue Jul 10, 2018 8:21 am
by Tim Berardelli
Jim,

Check your dwell-as the rubbing block on the points wears the dwell increases and the timing becomes retarded-a .004 reduction in point gap will change the timing by 3 degrees.

Re: Idle RPMs

Posted: Tue Jul 10, 2018 9:36 am
by Ron LaDow
I keep beating this horse, but it's sill not dead:
DO NOT adjust the carbs first.
Do a complete tune up in the proper sequence, and adjust the carbs to suit what the specific values (valves and ignition) want.

Re: Idle RPMs

Posted: Wed Jul 11, 2018 4:45 am
by Neil Bardsley
Ron LaDow wrote:I keep beating this horse, but it's sill not dead:
DO NOT adjust the carbs first.
Do a complete tune up in the proper sequence, and adjust the carbs to suit what the specific values (valves and ignition) want.
That is what the link I posted suggests :)

Re: Idle RPMs

Posted: Fri Jul 13, 2018 4:58 pm
by Tim Berardelli
Jim,

Did you ever solve your low idle problem?

Re: Idle RPMs

Posted: Sat Jul 14, 2018 7:42 pm
by Jim Beam
Thanks for the responses. Car has been sitting in the garage and I haven't had time to attend to it. I really do not have the skills and am attempting to get it into my wrench for a couple of issues, the low idle RPM being one of them. In the meantime, I am wondering whether I can adjust the carb linkage to accomplish a higher idle RPM? This would be only a temp fix until the issue can be addressed further. Thanks again.

Re: Idle RPMs

Posted: Sat Jul 14, 2018 10:06 pm
by Ron LaDow
Jim,
If you bandaid it, it just makes the proper adjustments more difficult. Why not just get it to him and let him to the correct process?

Re: Idle RPMs

Posted: Sat Jul 14, 2018 10:18 pm
by Wes Bender
+1 on what Ron says. You would be adding a complication if you adjusted the linkage without knowing that it was the problem. You indicated the idle suddenly dropped to the 300 range. I'd let the wrench know everything you've told us and let him find out what took place. I'm assuming that your wrench is well qualified in these fine cars.