| losing power [message #220016] |
Mon, 26 August 2013 17:07  |
Glenn
Messages: 92
Registered: February 2004
Location: Northwestern Ontario
Karma: 2
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Intermitent problem of losing power. Also notice that the vacuum is down but may be related to increased throttle trying to overcome the problem,(all new vacuum hose and have checked for leaks/connection problems). Do not totally lose power but have trouble maintaining speed(55mph without considerably more throttle)even on level cruise. Comes and goes but the fuel pressure on gage remains constant.In tank pump with new filters. Do not think it is hot enough for vapour lock as it has happened when just starting out for the day.Does not seem to matter if fan clutch is on or off but had to put on old clutch as new one would not release. Running 91 octane gas. What you all think, carburator,crappy fuel or ignition problem????? Thanks for all opinions.
Glenn
HTH.........
Glenn
76 Glensbroke
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| Re: losing power [message #220017 is a reply to message #220016] |
Mon, 26 August 2013 17:13  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Sounds to me like stuck spark advance not working. Could be mechanical, vacuum or both. Remove cap and check and lubricate mechanism as needed. You can confirm first with timing light. Could be a sloppy timing chain as well would be similar symptoms.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: losing power [message #220018 is a reply to message #220016] |
Mon, 26 August 2013 17:21 |
winter
Messages: 247
Registered: September 2007
Location: MPLS MN
Karma: 0
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cracked intake?
Jerrod Winter
1977 Palm Beach
Green Jelly Bean
Twin Cities, Minnesota
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| Re: losing power [message #220031 is a reply to message #220016] |
Mon, 26 August 2013 19:21 |
habbyguy
Messages: 896
Registered: May 2012
Location: Mesa, AZ
Karma: 3
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Make sure the secondaries on the carburetor are opening, too.
Mark Hickey
Mesa, AZ
1978 Royale Center Kitchen
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| Re: losing power [message #220033 is a reply to message #220016] |
Mon, 26 August 2013 19:37 |
Glenn
Messages: 92
Registered: February 2004
Location: Northwestern Ontario
Karma: 2
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New motor, block off plates on intake, if i punch it secondaries open, will check vac advance. no internet but using campground computer so will check back. thanks
glenn
HTH.........
Glenn
76 Glensbroke
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| Re: [GMCnet] losing power [message #220081 is a reply to message #220017] |
Tue, 27 August 2013 07:02 |
Steven Ferguson
Messages: 3447
Registered: May 2006
Karma: 0
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I'm chiming in with John on this one. Recheck your timing, start at 12 deg
initial. Inspect your mechanical advance mechanism, it may be rusted and
binding. Sooner or later, most do.
Steve F.
On Mon, Aug 26, 2013 at 3:13 PM, John R. Lebetski <gransport@aol.com> wrote:
>
>
> Sounds to me like stuck spark advance not working. Could be mechanical,
> vacuum or both. Remove cap and check and lubricate mechanism as needed.
> You can confirm first with timing light. Could be a sloppy timing chain
> as well would be similar symptoms.
> --
> John Lebetski
> Chicago, IL
> 77 Eleganza II
> Source America First
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Take care,
Steve
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| Re: [GMCnet] losing power [message #220082 is a reply to message #220081] |
Tue, 27 August 2013 07:19 |
Bruce Hart
Messages: 1501
Registered: October 2011
Location: La Grange, Wyoming
Karma: 5
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When checking the mechanical advance mechanism, you should be able to twist
the rotor , let go, and it should snap back to original position. If it
hesitates at all the distributor shaft passing through the bushing is most
likely gummed up.
On Tue, Aug 27, 2013 at 6:02 AM, Steven Ferguson <botiemad11@gmail.com>wrote:
> I'm chiming in with John on this one. Recheck your timing, start at 12 deg
> initial. Inspect your mechanical advance mechanism, it may be rusted and
> binding. Sooner or later, most do.
> Steve F.
>
>
> On Mon, Aug 26, 2013 at 3:13 PM, John R. Lebetski <gransport@aol.com>
> wrote:
>
> >
> >
> > Sounds to me like stuck spark advance not working. Could be mechanical,
> > vacuum or both. Remove cap and check and lubricate mechanism as needed.
> > You can confirm first with timing light. Could be a sloppy timing chain
> > as well would be similar symptoms.
> > --
> > John Lebetski
> > Chicago, IL
> > 77 Eleganza II
> > Source America First
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
> >
>
>
>
> --
> Take care,
> Steve
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Bruce Hart
1976 Palm Beach
Milliken, Co
GMC=Got More Class
51st State? Northern Colorado!
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Bruce Hart
1976 Palm Beach
1977 28' Kingsley
La Grange, Wyoming
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| Re: losing power [message #220132 is a reply to message #220016] |
Tue, 27 August 2013 16:56 |
Glenn
Messages: 92
Registered: February 2004
Location: Northwestern Ontario
Karma: 2
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Member |
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turns out to be mechanical advance. Can I access everything from the top or do I need to pull distributor? Also whats the best to lube it with?Thanks
Glenn
HTH.........
Glenn
76 Glensbroke
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| Re: losing power [message #220185 is a reply to message #220016] |
Wed, 28 August 2013 09:31 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Senior Member |
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If it's the weight pivots and pins and rub areas, you can put a bit of grease on your finger and apply a film, thin so barely visible. If it's the concentric shafts you could try a spout oiler, but the right way is to remove and knock out the roll pin and separate to clean and grease. Pay attention to thrust washers as reverse rotation makes force opposite of Chevy. I have Synpower so that is what I'd use.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: losing power [message #220361 is a reply to message #220185] |
Thu, 29 August 2013 15:13 |
Glenn
Messages: 92
Registered: February 2004
Location: Northwestern Ontario
Karma: 2
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Member |
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Well it was the mechanical advance that was hanging up. I pulled the distributor and cleaned, greased etc etc etc all under the watchful eye of the master from Coldwater. Thanks to all that replied.
Glenn
HTH.........
Glenn
76 Glensbroke
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