Fuel Issues?

[rebootej]

Hi guys i need some help.

I recently rebuilt the 318 in my 74 Satellite Sebring and upgraded with a mild cam, intake and 4bbl carb. The engine runs great while cruising in the country but in town after waiting at several lights the idle becomes very rough and will occasionally die on me. I have a fuel filter in line after the pump before the carb and i can see it has become almost empty. But after getting back on the highway for a few miles the idle is better and the filter is full of fuel again.

Any ideas? Is my pump going bad already? My idle to low? Any help would be greatly appreciated. Thank you.

 

[Propwash]

Edelbrock carb by chance? Sounds like it's vapor locking or a fuel boil issue would be my first guess.....Carb spacer and block off the heat crossovers would cure that issue. So would a return line. Another symptom of that would be slow/hard to start after sitting for more than a couple minutes.

Could be a vacuum leak as well....Nice place for that to happen is around the intake or carb base. Spray some starting fluid around each and listen for a rise of RPM or use a soapy solution when it's cool and look for bubbles.

 

[RustyRatRod]

Yeah sounds like the fuel is overheating. Check where you have the lines run. If they are close to things that get really hot such as exhaust components, rerouting them would be a good idea. Sometimes even insulating the lines is not a bad idea. As an engine's performance goes up, the heat it generates also goes up.

 

[67 coronet]

by what you explained i think rusty is right.just follow your fuel line from the carb back.anyplace where it gets close to the exhaust use some exhaust wrap(pretty cheep) and see if it solves your problem.most common problem spot is if you put headders on.gets really close to the lines under the passenger fire wall at the frame.

 

[rebootej]

Thank you guys, i did wonder about vapor lock, Ive head of it but never experienced it. It definitely does get worse after turning the engine off for a few min. I did forget to say i have headers too. The are that the fuel line runs along the body frame next to the header, is that to close? And yes it is an Eldelbrock carb on a performer intake. Not very happy with it so far.
Thank you for all the the quick replies and great advice guys!

 

[coloradodave]

I wouldn't be so quick to blame the carburetor for a problem that is very likely from another source. The suggestions above are good ones. There are thousands, if not millions of AFB style carbs out there working just fine. Do the diagnostic work before throwing new parts at it.

 

[RustyRatRod]

Right on, Dave. Even though I'm no fan of crapplebrocks, you cannot deny there are millions of them in use and they are good carburetors in their element. Their element is just not MINE. lol

I wouldn't be so quick to blame the carburetor for a problem that is very likely from another source. The suggestions above are good ones. There are thousands, if not millions of AFB style carbs out there working just fine. Do the diagnostic work before throwing new parts at it.

 

[rebootej]

Yes i will try shielding the fuel line first and a spacer for the carb first. But as a fact before this happened i was already researching other carbs. Thanks again guys, let you know how it goes working on it right now.

 

[440+6]

The conditions you mentioned sure dose sound like vapor lock, I had a car did it all the time.
The guys are right get the fuel lines away from any heat, insulate, whatever you need to do, that's exactly what I did and never had the problem again.

 

[tallhair]

Right on, Dave. Even though I'm no fan of crapplebrocks, you cannot deny there are millions of them in use and they are good carburetors in their element. Their element is just not MINE. lol

just curious if you are in the majority on the carter designed carbs here and why you and maybe everyone else thinks the holly's are better? I ran carter carbs almost exclusively (exception was a 780 holly dual feed i ran on a 413 mildly modded and later a 440 with a Edelbrock Torker single plane I've had since 81) for years on stock HP 383, 400, 413, and 440's on stock intakes and never had problem with one and never experienced any lack of throttle response or felt like they weren't pulling through the RPM range. In my experience i rarely had to mess with them and when one had set for years or even decades they were fairly easy to rebuild. Holly's on the the other hand, we tried rebuilding a few of them w/o success. My dad may have rebuilt my 780 but if he didn't it was the only one that ever ran right afterward. I'm sure this was lack of knowing what to do, or just not doing it good enough. Anyway, i've run the edelbrock version and they always worked great for me.

 

[rebootej]

Hey guys been away at work. Put some insulation on the fuel line along the body frame and a spacer on the carb. It helped, but the problem is still there, just not as bad. Any other places i should check? Thank you.

 

[RustyRatRod]

It's not just Carters. It's ANY carburetor that uses metering rods. I don't care how many different sets of springs you have, once you pass a certain point of low vacuum signal, metering rods have a difficult time at best of keeping up. The Carter carbs are better suited to mild/moderat applications with camshaft duration figures under 240* @ .050. They simply are not made for low vacuum applications. But as I said, used in their element they work well.

just curious if you are in the majority on the carter designed carbs here and why you and maybe everyone else thinks the holly's are better? I ran carter carbs almost exclusively (exception was a 780 holly dual feed i ran on a 413 mildly modded and later a 440 with a Edelbrock Torker single plane I've had since 81) for years on stock HP 383, 400, 413, and 440's on stock intakes and never had problem with one and never experienced any lack of throttle response or felt like they weren't pulling through the RPM range. In my experience i rarely had to mess with them and when one had set for years or even decades they were fairly easy to rebuild. Holly's on the the other hand, we tried rebuilding a few of them w/o success. My dad may have rebuilt my 780 but if he didn't it was the only one that ever ran right afterward. I'm sure this was lack of knowing what to do, or just not doing it good enough. Anyway, i've run the edelbrock version and they always worked great for me.

 

[Propwash]

I take it you didn't have the time to block the heat crossovers? What kind of spacer did you go with? Some spacers are made to upgrade performance/efficiency, some for heat dissipation issues.

 

[rebootej]

Correct i did not have time to block the bypasses. How do you do that? The spacer i got is rubber made by edelbrock advertised for use where heat is an issue.

 

[Propwash]

Here's a set from Mopar that come with a stainless block off plate.

http://www.summitracing.com/parts/dcc-4286569/overview/

I've found the wood based spacers work real well:

http://www.jegs.com/i/Edelbrock/350/8724/10002/-1?parentProductId=743637

Heard the layered work pretty well...

http://www.jegs.com/i/JEGS+Performance+Products/555/154055/10002/-1?CAWELAID=1710675586&catargetid=1784155633&&cagpspn=pla&gclid=CO33xtuqnrUCFaI-MgodYXwA3Q

 

[rebootej]

Thank you very much. Ill have to give those a try.

 

[Propwash]

Thank you very much. Ill have to give those a try.

Not a problem...I fought with the same issue with my Coronet for a while..Kept getting worse over the years. Thought it was the cooling system...nope, then timing....nope, then a carb issue...nope, then a vacuum leak issue....nope. Finally saw the light and figured out it was the crap ethanol laced fuel I was putting in my tank that was progressively getting worse.

I have a friend with a small block Challenger that used tin from a coffee can to block his crossovers. Two years later it's still holding.

 

[67 coronet]

Not a problem...I fought with the same issue with my Coronet for a while..Kept getting worse over the years. Thought it was the cooling system...nope, then timing....nope, then a carb issue...nope, then a vacuum leak issue....nope. Finally saw the light and figured out it was the crap ethanol laced fuel I was putting in my tank that was progressively getting worse.

I have a friend with a small block Challenger that used tin from a coffee can to block his crossovers. Two years later it's still holding.

i think you hit a nail on the head there prop.the new fuels vaporise much easyer then older mixes.i think we are going to see this problem become more common as the years go on and fuel %'s change even more.

 

[Propwash]

I hope so '67. Good to go thus far. Nothing worse than being a parts changer and not a mechanic. Chasing symptoms instead of fixing actual problems. Frustrating, but i'm sure we've all been down that road at one point or another.