Runs Great...Until it Doesn't

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Feb 21, 2021 | 06:52 AM

'62 Susie Q

Thread Starter

Mountain Pass

Joined: Apr 2020

Posts: 105

Likes: 10

Runs Great...Until it Doesn't

Back for some more sage advice. As some here may recall, I recently went through trials and tribulations getting through a "tune up" on my signature truck. Long story short, after a 1904 Holley rebuild, replacing all ignition components (I did finally give up on the points and put an electronic ignition module in the stock distributor), and an oil pan gasket (don't get me started), the truck ran great. She cranks right up and drives great for about 10-15 mins. Then, she starts running rough and stalls out as I take my foot off the gas. Short of removing the carb, again, and going through it in detail, is there any experience with this out there or advice for where to start on this problem? As always, thanks in advance.

Feb 21, 2021 | 10:25 AM

robertrpeak

Tuned

Joined: Jul 2016

Posts: 469

Likes: 60

From: TN.

After it shuts off, check plugs for fire and go from there.

Feb 21, 2021 | 10:30 AM

hiball3985

Logistics Pro

Joined: Mar 2005

Posts: 3,771

Likes: 80

From: tujunga, calif

X2, check for spark, could be the coil. Do you have a vented gas cap? Try driving it with the cap off to help eliminate fuel starving

Feb 21, 2021 | 10:42 AM

lizardman1

Laughing Gas

Joined: Jul 2007

Posts: 753

Likes: 133

From: Phoenix

Does the engine restart after rough run and stall? Does it keep stalling? Does the engine repeat this problem after cool down? For sure check for spark when after it stalls.
Just have to double check your ignition system for heat related spark issues.

Feb 21, 2021 | 12:25 PM

'62 Susie Q

Thread Starter

Mountain Pass

Joined: Apr 2020

Posts: 105

Likes: 10

Thanks to lizardman, hiball and robert for the troubleshooting tips! I went out and checked under the hood. I noticed some fuel stains on the intake manifold under the fuel bowl, but no leaks when the truck was cold. It's not cold here like elsewhere in the country (low 30's today), but I cranked the truck up and let her high-idle with a little choke on to warm her up for 15 mins. Once warm the leaking fuel bowl revealed itself. I was worried after cautions from others that cranking down on the fuel bowl screws on that Holley 1904 could warp the housing. I guess I just didn't get quite enough on them to prevent the leak and thus fuel-air mixture problem induced by it. I had an extra fuel bowl gasket so I swapped it out for good measure and put another 1/4 turn on the screws holding the fuel bowl on. Got two birds with one stone: no more leak and no more stalling once warm. Thanks again, and again!

Feb 22, 2021 | 01:43 PM

624WD

More Turbo

Joined: Aug 2013

Posts: 562

Likes: 112

From: Shelburne, NH

Good! Always learning...

Feb 22, 2021 | 05:51 PM

daveengelson

Lead Driver

Joined: Aug 2003

Posts: 6,305

Likes: 18

From: Boulder Creek, Ca

Perhaps too much fuel resulting in flooding particularly if using the chock? Suggest check float bowl lever, should be just below float site screw, with vehicle level. Not familiar with the ignition system U installed but when I went to electronic ignition the spark gap ran around .045. I would gently close the idle mixture screws then open approx. 1 to 1 1/2 turns and fine tune once engine is running, Finally check the timing, I use my back yard mechanic method by removing #1 plug, insert finger in opening and as soon as compression forces my finger out of the opening I immediately stop and check the timing mark on the harmonic balance to the position of the rotor and which plug is set to fire, if all is well marks should be aligned with #1 cylinder. Keeping in mind, an adjustment in timing one should adjust idle mixture and vise versa. Anyhow, had an urge to chime in offer food for thought>?