Arrrrggg! carb blowing gas 4ft high! timing? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**guyryan100** · 01-02-2005, 02:38 PM

Trying to test-fire my new 350 for the first time. Carb is blowing gas out the top, which I assume means that my timing is badly off. I've tried 3 times to set the timing. Here's how I did it...

I remove plug #1, had the wife turn the engine over (with the starter - not by hand) while I felt the air passing in/out of the plug hole. I had her stop the engine prior to the larger of the two pursts of air, and then I turned the engine forward by hand until I reached TDC, which I measured via a curved piece of ire through the hole. I then lined up my HEI dist pointing to the #1 plug wire, checked my firing order again. I'm sure the firing order is correct. Am I 180* out? If so, can I just turn the dist 180*?

incoma · 01-02-2005, 03:18 PM

Well, if you are backfiring through the carb, you are most likely on #6 instead of #1. To be sure, you'd have to pry your timing cover out enough to see where the timing chain dots lined up. There was a thread started within the last week that had great detail.

**guyryan100** · 01-02-2005, 03:31 PM

well I found that if I give it a good advance, I get a backfire through the exaust. If I retard it a bit, the gas out the carb gets a bit higher. So I must be well-off the mark.

special70gmc · 01-02-2005, 03:39 PM

no is the gas streaming out of the bowl vents? the tubes on either side of the barrels? if so ur timing has nothing to do with it. if so ur floats are either set too high or there stuck. this happend to me in the past sure does make a mess! -kyle

**guyryan100** · 01-02-2005, 03:49 PM

if I disconnect the +wire from the HEI I don't get any fuel spray - it's only when the ignition is charged.

GMC AMI · 01-02-2005, 03:55 PM

Must be timing is off. Why did you not look at the timing mark on the tab when you did tdc? Instead of a wire. Just put it on zero with Number 1 on compression stroke.

*rage'nrat638* · 01-02-2005, 03:59 PM

Quote:

Originally Posted by Mike Files

Must be timing is off. Why did you not look at the timing mark on the tab when you did tdc? Instead of a wire. Just put it on zero with Number 1 on compression stroke.

hey mikey !!!!!!!!!! wazzzzzzzzzzzzzup.....

**guyryan100** · 01-02-2005, 04:14 PM

No timing mark tab :-( I've got the water pump off now and am pulling the timing cover. Then I'll know for sure it's timed correctly. wish I'd done this before I put the core, radiator, grill, and antifreeze in!

GMC AMI · 01-02-2005, 04:52 PM

Bummer, good luck man. When you dropped the distrb. in place did you back up the rotor button about 15 degrees prior to setting down? This would need to be done or your timing will not be correct. It rotates in to place as the gears mesh. If taking the timing cover off it would be a great time to put the timing tab on the cover. Takes a lot of the guess work out of the equation.

Blue Beard · 01-02-2005, 05:04 PM

No timing tab, how are you going to check timing with it running....

Hope you set the plug wires in the right spots, different on the points or hei dist.

**guyryan100** · 01-02-2005, 05:07 PM

Quote:

Hope you set the plug wires in the right spots, different on the points or hei dist.

Huh? 18436572 - isn't this independant of the dist type?

Blue Beard · 01-02-2005, 05:33 PM

HEI dist has the #1 plug wire in a different location than a points type.

incoma · 01-02-2005, 05:40 PM

Techinically, you can place the #1 plug wire whereever you want to on the distributor. You just have to properly align the rotor to hit it advanced of tdc. The location of #1 isn't different between HEI and points.

71gmcfanatic · 01-02-2005, 07:36 PM

sounds like you could be off by 180 if its firing out the carb the engine is firing when the valves are open.

dons454s · 01-02-2005, 08:47 PM

You dont happen to have your rocker extremly over tightened do you ?? Just a thought because that would do it.

jimfulco · 01-03-2005, 01:37 AM

If you think it's 180* out, just swap each plug wire with the one directly opposite it on the cap. No need to pull the distributor.

GMC AMI · 01-03-2005, 08:17 AM

Quote:

Originally Posted by jimfulco

If you think it's 180* out, just swap each plug wire with the one directly opposite it on the cap. No need to pull the distributor.

Easy enough to pull the dist. and set it correctly. Do it right not the shortcut way. Install the timing tab also. If nothing else it is a great way to learn by doing yourself, Bravo.

01-02-2005, 03:39 PM	#4
special70gmc Registered User Join Date: Sep 2002 Location: long island, new york Posts: 1,333	no is the gas streaming out of the bowl vents? the tubes on either side of the barrels? if so ur timing has nothing to do with it. if so ur floats are either set too high or there stuck. this happend to me in the past sure does make a mess! -kyle __________________ 1986 c-10 swb 5/7 drop 20'' coys 1958 belair 2door

01-02-2005, 04:52 PM	#9
GMC AMI Registered User Join Date: Apr 2004 Location: The Other Maine! Posts: 2,236	Bummer, good luck man. When you dropped the distrb. in place did you back up the rotor button about 15 degrees prior to setting down? This would need to be done or your timing will not be correct. It rotates in to place as the gears mesh. If taking the timing cover off it would be a great time to put the timing tab on the cover. Takes a lot of the guess work out of the equation. __________________ 1968 Chevy 4x4 307 4 speed Last edited by GMC AMI; 01-02-2005 at 04:57 PM.

01-02-2005, 05:04 PM	#10
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	No timing tab, how are you going to check timing with it running.... Hope you set the plug wires in the right spots, different on the points or hei dist. __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-02-2005, 05:33 PM	#12
Blue Beard Registered User Join Date: Jan 2003 Location: Washington State Posts: 8,834	HEI dist has the #1 plug wire in a different location than a points type. __________________ 1970 Chev CST 2003 Harley Fatboy 1975 Chevrolet Step Van 1956 Chev Bel Air 1977 Blazer 2WD For Sale $3000.00 1978 Blazer 2WD For Sale $7000.00 1978 Silverado 2005 Monte Carlo

01-02-2005, 07:36 PM	#14
71gmcfanatic Registered User Join Date: Dec 2002 Location: Marysville, WA Posts: 101	sounds like you could be off by 180 if its firing out the carb the engine is firing when the valves are open. __________________ 1971 gmc 3/4 ton, 350, t350

01-02-2005, 02:38 PM	#1
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 481	Arrrrggg! carb blowing gas 4ft high! timing? Trying to test-fire my new 350 for the first time. Carb is blowing gas out the top, which I assume means that my timing is badly off. I've tried 3 times to set the timing. Here's how I did it... I remove plug #1, had the wife turn the engine over (with the starter - not by hand) while I felt the air passing in/out of the plug hole. I had her stop the engine prior to the larger of the two pursts of air, and then I turned the engine forward by hand until I reached TDC, which I measured via a curved piece of ire through the hole. I then lined up my HEI dist pointing to the #1 plug wire, checked my firing order again. I'm sure the firing order is correct. Am I 180* out? If so, can I just turn the dist 180*?

01-02-2005, 03:18 PM	#2
incoma Registered User Join Date: Mar 2004 Location: Lexington, KY Posts: 865	Well, if you are backfiring through the carb, you are most likely on #6 instead of #1. To be sure, you'd have to pry your timing cover out enough to see where the timing chain dots lined up. There was a thread started within the last week that had great detail.

01-02-2005, 03:31 PM	#3
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 481	well I found that if I give it a good advance, I get a backfire through the exaust. If I retard it a bit, the gas out the carb gets a bit higher. So I must be well-off the mark.

01-02-2005, 03:49 PM	#5
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 481	if I disconnect the +wire from the HEI I don't get any fuel spray - it's only when the ignition is charged.

01-02-2005, 03:55 PM	#6
GMC AMI Registered User Join Date: Apr 2004 Location: The Other Maine! Posts: 2,236	Must be timing is off. Why did you not look at the timing mark on the tab when you did tdc? Instead of a wire. Just put it on zero with Number 1 on compression stroke. __________________ 1968 Chevy 4x4 307 4 speed

01-02-2005, 04:14 PM	#8
guyryan100 Registered User Join Date: Sep 2001 Location: Cumming, GA Posts: 481	No timing mark tab :-( I've got the water pump off now and am pulling the timing cover. Then I'll know for sure it's timed correctly. wish I'd done this before I put the core, radiator, grill, and antifreeze in!

01-02-2005, 05:40 PM	#13
incoma Registered User Join Date: Mar 2004 Location: Lexington, KY Posts: 865	Techinically, you can place the #1 plug wire whereever you want to on the distributor. You just have to properly align the rotor to hit it advanced of tdc. The location of #1 isn't different between HEI and points.

01-02-2005, 08:47 PM	#15
dons454s Registered User Join Date: Nov 2004 Location: Claysburg, Pa Posts: 408	You dont happen to have your rocker extremly over tightened do you ?? Just a thought because that would do it.

01-03-2005, 01:37 AM	#16
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	If you think it's 180* out, just swap each plug wire with the one directly opposite it on the cap. No need to pull the distributor.

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