She won't idle...any ideas? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

briarpatch · 07-14-2005, 12:06 PM

Last night I replaced the leaky exhaust and intake manifolds without a hitch on the ’70 C10 with 250 L6. Exhaust doesn't blow into the engine compartment now and it sounds better. The problem I have created is the engine won't idle now. It just dies out if I let up on the accelerator. Nothing seems to have changed with the carburetor, or anything else that I can see.

Any ideas on what I should be looking for?

Thanks!

Jwill41 · 07-14-2005, 12:12 PM

possibly vacume leak around intake?

shifty · 07-14-2005, 01:45 PM

Does it continue after the engine heats up? Do you have a manual choke (top right-hand side of the dash)?

briarpatch · 07-14-2005, 02:04 PM

Quote:

Originally Posted by shifty

Does it continue after the engine heats up? Do you have a manual choke (top right-hand side of the dash)?

It has an auto choke. I have not let it run long enough to really heat up. The old ex. manifold did not have a working heat-riser, this one does. I will take it for a little ride this evening to see what happens when it is warm...

fastwillie 696969 · 07-14-2005, 02:38 PM

try readjuting the carb now that a new intake gasket is place maybe the carb was set for when the intake had a slight leak and now thats is seal readjustment might need to be and check your timing again

Mongo · 07-14-2005, 03:45 PM

I had the same problem on my 48 wilies that has a buick v6. the gasket under the carb. failed causing a major vacuum leak.

The damn thing would run great at about 1500rpm, but as soon as it went to idle it died....

briarpatch · 07-15-2005, 10:25 AM

Thanks for the input. I retightened the carb and manifold bolts and tweaked the carb adjustment screws a little. Was most likely vacuum and carb adjustment problem. It will idle now, but still needs a little more tweaking. Was most likely vacuum and carb adjustment problem.

gparmer · 07-15-2005, 11:38 AM

One way to check for vacuum leaks involves a spray bottle of starting fluid or even WD40. With the engine running you can direct the spray at potential sources of leaks like the intake port gaskets, carb gasket, fittings, etc. The engine will change speeds when you spray around a leak. Usual caveats related to fire and extreme caution apply.

07-14-2005, 12:06 PM	#1
briarpatch Registered User Join Date: May 2005 Location: Beauregard, AL Posts: 64	She won't idle...any ideas? Last night I replaced the leaky exhaust and intake manifolds without a hitch on the ’70 C10 with 250 L6. Exhaust doesn't blow into the engine compartment now and it sounds better. The problem I have created is the engine won't idle now. It just dies out if I let up on the accelerator. Nothing seems to have changed with the carburetor, or anything else that I can see. Any ideas on what I should be looking for? Thanks! __________________ ------------------------------------- Tim '67 C/10, '04 Tahoe -------------------------------------

07-14-2005, 12:12 PM	#2
Jwill41 Registered User Join Date: Aug 2002 Location: Farmers Branch, Tx Posts: 1,009	possibly vacume leak around intake? __________________ http://www.picturetrail.com/jwill41 67 1/2 ton GMC short step side 68 1/2 ton Chevy long fleet side 72 1/2 ton Chevy Suburban 99 1/2 ton Chevy Suburban founder (and only member) of the primer/clearcoat club

07-14-2005, 01:45 PM	#3
shifty Questionable Join Date: Mar 2005 Location: Atlanta Posts: 13,376	Does it continue after the engine heats up? Do you have a manual choke (top right-hand side of the dash)? __________________ If I've got anything up for grabs, it'll be here: 7-hole gauge cluster for a 67-72 p/u FREE (link) I can't check the forum daily. If I don't reply to you within 24 hours, drop me a PM! I'm (hopefully) still alive and will reply faster to a PM.

07-14-2005, 02:38 PM	#5
fastwillie 696969 ~Rest In Peace~ Join Date: May 2005 Location: CALIFORNIA NOR CAL Posts: 9,707	try readjuting the carb now that a new intake gasket is place maybe the carb was set for when the intake had a slight leak and now thats is seal readjustment might need to be and check your timing again __________________ is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex

07-14-2005, 03:45 PM	#6
Mongo YES_____NO Join Date: Jul 1999 Location: Somewhere in the vicinity of betelgeuse Posts: 7,351	I had the same problem on my 48 wilies that has a buick v6. the gasket under the carb. failed causing a major vacuum leak. The damn thing would run great at about 1500rpm, but as soon as it went to idle it died.... __________________ People many not remember what you said or what you did, but they will remember the way you made them feel. - unknown Cause, remember: no matter where you go... there you are. - Buckaroo Banzai 1984 Help support the board

07-15-2005, 10:25 AM	#7
briarpatch Registered User Join Date: May 2005 Location: Beauregard, AL Posts: 64	Thanks for the input. I retightened the carb and manifold bolts and tweaked the carb adjustment screws a little. Was most likely vacuum and carb adjustment problem. It will idle now, but still needs a little more tweaking. Was most likely vacuum and carb adjustment problem. __________________ ------------------------------------- Tim '67 C/10, '04 Tahoe -------------------------------------

07-15-2005, 11:38 AM	#8
gparmer Registered User Join Date: Jun 2005 Location: Auburn, AL Posts: 1	One way to check for vacuum leaks involves a spray bottle of starting fluid or even WD40. With the engine running you can direct the spray at potential sources of leaks like the intake port gaskets, carb gasket, fittings, etc. The engine will change speeds when you spray around a leak. Usual caveats related to fire and extreme caution apply.



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