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01-30-2008, 10:25 AM | #1 |
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Location: Georgetown , TX
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High idle speed
My truck is running fine but it idels almost at 1200 rpm. the electric choke is not hooked up and the timing is almost at 18* btdc. whats going on?
really need some help with this thanks ahead of time cody
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70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb |
01-30-2008, 11:40 AM | #2 |
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Location: Federal Way, WA
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Re: High idel speed
check for vacuum leaks, either around the base of the carb or any vacuum lines, possibly internal vacuum leak in the carb. 18 degree's is advanced alot is the advance still hooked up when your setting the timing.
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1970 K-10 400CID, to much cam--not enough compression Stan's Headers and a 4" lift / 1990 R1500 Suburban 4X4, 350CID with vortec heads, edlebrock intake, TBI, 10:1 compression and Stan's Headers "The probability of someone watching you is directly proportional to the stupidity of your actions" |
01-30-2008, 12:58 PM | #3 |
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Re: High idel speed
Turn down the idle speed?
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72 C2500 LWB 402 Sierra Grande 05 Odyssey 08 Tundra |
01-30-2008, 01:51 PM | #4 |
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Re: High idel speed
I had a similar problem and fixed it by putting on a heavier return spring.
Danny |
01-30-2008, 02:05 PM | #5 |
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Location: Federal Way, WA
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Re: High idle speed
yes, I would definetly return the throttle by hand to see if it can come back farther, if it does use a heavier spring, good idea shyguy
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1970 K-10 400CID, to much cam--not enough compression Stan's Headers and a 4" lift / 1990 R1500 Suburban 4X4, 350CID with vortec heads, edlebrock intake, TBI, 10:1 compression and Stan's Headers "The probability of someone watching you is directly proportional to the stupidity of your actions" |
02-01-2008, 08:30 AM | #6 |
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Location: Georgetown , TX
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Re: High idle speed
Has after market heavy spring, brand new carb, idel screw is backed all the way out
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70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb |
02-01-2008, 11:52 AM | #7 |
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Location: Santa Maria, Ca.
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Re: High idle speed
Your secondaries are partially open could be bent rod or just dirty or out of adjustment try to manually close them or look down in the carb to see if one of the screws has come off the butterflies. You should also check the choke cam to make sure it is not holding the throttle open
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69 Chevy 4x4 383 Power Last edited by haysonj; 02-01-2008 at 12:00 PM. |
02-01-2008, 12:40 PM | #8 |
what knocking sound?
Join Date: Feb 2005
Location: good ol North Dakota
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Re: High idle speed
Something you could try is to hook up the choke and turn the choke housing a quarter turn counterclockwise (lean). This should make sure the choke isn't part of the problem. My 72 did the same thing and this fixed it.
Kage
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1968 C-10 1953 belair two-door post 1955 chevy 3600 big window 1950 studebaker starlite coupe 1968 Impala SS |
02-01-2008, 12:59 PM | #9 | |
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Re: High idle speed
Quote:
I would remove the carb and check to make sure that butterfly closes almost shut when at rest. Should have just a small clearance. If all the mechanicals check out, then possible vacuum leak. Don't overlook cracked hoses or possible transmission modulator if auto. |
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02-05-2008, 10:56 AM | #10 |
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Location: Georgetown , TX
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Re: High idle speed
ok fixed the high idel, the choke cam was holding the throttle open. but now i have a timing question, is the listed 8* btdc before or after you hook up the vacuum advance back up? should i be ideling at 8 with everything buttoned up? or ideling at 8 with the vacuum pluged and then it jump to 10 or 12 with it connected?
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70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb |
02-05-2008, 12:41 PM | #11 |
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Location: Idaho
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Re: High idle speed
8* base timing, so with vac advance disabled.
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72 C2500 LWB 402 Sierra Grande 05 Odyssey 08 Tundra |
02-06-2008, 09:46 AM | #12 |
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Location: Georgetown , TX
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Re: High idle speed
thanks cruiserman, is that what most of you are running? with what i put on it should i run somthing different?
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70 Chevy C-10 short step 250/3 on the tree Owned: 71 longbed Cheyenne 70 swb |
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