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#1 |
I survived Dead Man's Curve.
Join Date: Apr 2006
Location: The Nine-Five-687
Posts: 389
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Engine Hesitation?
Well, the 350 has been in my truck for a week now. It runs pretty good except for a hesitation. If I smoothly accelerate, it generally does ok.
If I romp on it a little harder, it tends to misfireas if a spark plug isn't connected I suppose. The engine quiets down and fights for gas and if I don't handle the situation right, it can actually stall completely. This happens especially early morning, when it's cold outside. The intake manifold is stock, I haven't even touched it, and I don't hear any vacuum leaks. The Holley Street Avenger on top of it is on correctly and tightly. I've been informed that Holleys tend to be too lean for a 350 and the jets need replacing. Does anyone agree with this? Also, the distributor is fine, fuel filters are new, carb adjustments are correct, and I have not had any previous fuel travelling problems with the 6cyl that was in there.
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"The people should not be afraid of their government. The government should be afraid of it's people." "The Hurricane" 1967 Chevrolet C10 350 Eight Cylinder, 700R4 BowtieOverdrive Cherry Bomb... Disturbing the Peace Since 1968. ![]() Last edited by ThatOneBlue67; 10-23-2006 at 06:08 PM. Reason: grammar review |
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#2 |
I survived Dead Man's Curve.
Join Date: Apr 2006
Location: The Nine-Five-687
Posts: 389
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Re: Engine Hesitation?
I started her up to go to work today and thought I heard a whistle, as if there amy be a vacuum leak. I'm thinking of replacing the intake gaskets in the near future. If not this, anythign else?
Again, things that I know are OK: -Distributor -Spark plugs and wires -Carburetor bolted on and hooked up correctly (for the most part) -Choke is always at wide open throttle. *I read somewhere that the secondary vacuum spring may be too weak or to stiff for my application. Anyone else?
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"The people should not be afraid of their government. The government should be afraid of it's people." "The Hurricane" 1967 Chevrolet C10 350 Eight Cylinder, 700R4 BowtieOverdrive Cherry Bomb... Disturbing the Peace Since 1968. ![]() |
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#3 |
Registered User
Join Date: Jan 2006
Location: Kaufman, Tx
Posts: 827
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Re: Engine Hesitation?
Call the holley tech line. They are great and will give you all the little tricks for that carb. I put the SA 670 on my 350, and after a few calls & tuning sessions, mine works great. I'll bet that with the new engine, the tuning parameters changed. If I remember correctly, I was talking to Ricky. But that was a few months ago.
Jay
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You only need two tools in life - WD-40 and Duct Tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape. If a hammer doesn't fix it, you have an electrical problem! Slot Cars, 1:24 Scale, 100MPH@100,000RPM, fastest things on wheels! ![]() |
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#4 |
4 eyed fever
Join Date: Jul 2005
Location: Eureka, Nevada
Posts: 500
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Re: Engine Hesitation?
Mine had the same type of hesitation. A mechanic told me the carb was warped and it had a serious vac leak. He offered to put a rebuilt qjet in it for only $680! I opted not to do it. After putting in a recently rebuilt carb, the same thing happened. I had to set the timing all the way to about 25 BTDC. I think the PO put the distributer in wrong. I think he had it at TDC on the exhaust stroke instead of compression/fire. I haven't had a chance to check it yet, but it runs great when set waaaay advanced.
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1971 GMC 2500 4x4 1972 GMC Sierra Grande 1/2 t 4x4-#1 son's truck. Recently completed resto. 4 YO daughter," Daddy, I like your truck better than Mom's." (2000 F350-ranch truck) Smart kid!! |
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#5 |
I survived Dead Man's Curve.
Join Date: Apr 2006
Location: The Nine-Five-687
Posts: 389
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Re: Engine Hesitation?
I guess I'll call the Holely tech line. It staleld on me again today twice. I sure hope it's just me and it isn't getting worse
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"The people should not be afraid of their government. The government should be afraid of it's people." "The Hurricane" 1967 Chevrolet C10 350 Eight Cylinder, 700R4 BowtieOverdrive Cherry Bomb... Disturbing the Peace Since 1968. ![]() |
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#6 |
Junior Member
![]() Join Date: Aug 2006
Location: California Shasta County
Posts: 109
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Re: Engine Hesitation?
You say the distributor is ok but what is the timing set at, and are you sure you got the correct base gasket on the carb?
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#7 |
Registered User
Join Date: Aug 2006
Location: Bakersfield,CA
Posts: 7,893
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Re: Engine Hesitation?
does it still due it even after the engine is fully warmed up???? cause mine used to do it and still kinda does, but its nice and smooth once its fully warmed just food for thought hope you get it fixed
-steven ![]()
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
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#8 |
Registered User
Join Date: Jun 2002
Location: Knoxville Tenn.
Posts: 3,058
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Re: Engine Hesitation?
Did you install the Holley on a Q-jet manifold?
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56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer |
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#9 |
Next project: 1970 K10
Join Date: Feb 2004
Location: Fort Collins, Colo 80524
Posts: 6,685
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Re: Engine Hesitation?
I was wondering that too.....square flange carb on a spread bore manifold? Get a can of carb cleaner and start checking for vacuum leaks.
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Bob 1970 Chevy K10 LWB "Goldie" 350/TH350 next project!! 1981 Chevy C10 LWB 355/TH350 - My son's truck LS SWAP FORUM! Tons of LS swap info here! PLEASE CLICK HERE TO SUPPORT THE GREATEST BOARD ON THE NET! CLICK HERE FOR THE FAQ INDEX by KRUE |
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#10 |
71 rustless in texas
Join Date: Aug 2004
Location: Houston, TX
Posts: 257
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Re: Engine Hesitation?
I had this exact same thing happen to me a couple of years ago. I had just put a Holly on a Q-jet manifold. if you look at both sides of the carb at the manifold you'll see the manifold "disappears" under the carb. There is a gigantic hole there under the carb and will cause the thing to hesitate real bad at idle when cold. It will appear to get better as the engine heats up. You need to either get a manifoldadaptot to adapt the Q-jet manifld to a spread bore or you can look for a isolation plate for the spread bore. Put gaskets on both sides and it will stop the leak. this way isn't really the right way but it will work.
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