| Does 780rpms idle/10degrees tdc 17inches vac sound ok [message #277564] |
Sat, 09 May 2015 15:26  |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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I was wondering if a good basis point of 780 rpms, 10 degrees tdc 17 inches vac, and idle mixture screws at 2.75 turns from seat is a decent starting point for a test drive. I am not flooding out anymore nor stalling. I did have the vac advance line plugged. I also seated a screw tighter for the contact point of the accelerator pedal line. Before the screw never met the contact point. It basically kept the idle stronger when in park. Just wondering if it might be time for a test drive??? Still no electric choke installed but the farmer's choke is working pretty decent. Any other things to look for from your guys experiences would be most helpful. Thanks,also this was my best vac measurement as I tried a few other settings
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
[Updated on: Sat, 09 May 2015 15:29] Report message to a moderator |
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| Re: Does 780rpms idle/10degrees tdc 17inches vac sound ok [message #277644 is a reply to message #277564] |
Mon, 11 May 2015 10:02  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Perhaps you should slow the idle to the low 600''s, then set the mixture. At the higher speed you may be partly off the idle circuit. Set mix screws each for best speed and lean to the point just where RPM would start to drop but does not Adjust L and R slightly each move. for best emissoins lean each side for slight 25 RPM drop. Then reset final base idle w speed screw. Confirm fast idle screw, choke and choke pull off (important) are set as well.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Does 780rpms idle/10degrees tdc 17inches vac sound ok [message #277683 is a reply to message #277564] |
Mon, 11 May 2015 18:09 |
budworks521
Messages: 137
Registered: October 2013
Location: Grand Rapids MI 1974 Pain...
Karma: 4
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Senior Member |
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unfortunately I have not much experience at this and will attempt to understand it more. I am finding that it is difficult to find qualified old school techs to fix my coach and most go by "sound of idle and sound of timing ". Thanks for all the input
1974 Painted Desert
455 upper half rebuild
constant project inexperienced mechanic
Grand Rapids Mi
Always trying to learn
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| Re: Does 780rpms idle/10degrees tdc 17inches vac sound ok [message #277698 is a reply to message #277564] |
Mon, 11 May 2015 20:25 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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budworks521 wrote on Sat, 09 May 2015 14:26I was wondering if a good basis point of 780 rpms, 10 degrees tdc 17 inches vac, and idle mixture screws at 2.75 turns from seat is a decent starting point for a test drive. I am not flooding out anymore nor stalling. I did have the vac advance line plugged. I also seated a screw tighter for the contact point of the accelerator pedal line. Before the screw never met the contact point. It basically kept the idle stronger when in park. Just wondering if it might be time for a test drive??? Still no electric choke installed but the farmer's choke is working pretty decent. Any other things to look for from your guys experiences would be most helpful. Thanks,also this was my best vac measurement as I tried a few other settings
If you don't need an emissions check, I would put it in drive with the park brake set and adjust the idle mixture screws in until the idle speed slows down or become unstable--then back out a turn. A little rich will be much better than setting it lean as GM advised at the time--no need to punish yourself for emissions if you don't need to.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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