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Hard start after hot soak L6

Are all the lines new?, Have you tried putting an in line electrical fuel pump?
Have you tried to talk to Joe whom has lived in the Tucson,Az. area with the Stovebolt since the late 70's.

Here are a few shots of where I have my inline pump while keeping the mechanical one. showing tank location to starter button IO give it a boost with.
Chevy was in Az. this weekend 109 and not a sputter there and back.
 

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Lakeroadster said:
How about posting up some engine photos... curious about your fuel line routing and its location to heat sources, as was previously discussed?

After I built my Model A hot rod (about 2 decades ago) I took it to Frank Johnson Carburetor & Ignition Shop that was "the place" all the guys I knew said was the best of the best to have it dyno. tuned at.

Frank (a certified "wise" been there done that older fella) went on and on about what a great job I did routing the fuel line away from heat sources....

Hard Hot Starting Problems

As for hot starting problems, the carburetor is seldom to blame. A hot start condition is usually the result of too much heat in the vicinity of the carburetor, fuel lines or fuel pump. Heat causes the fuel in the fuel lines, carburetor bowl or pump to boil. This creates a "vapor lock" condition which can make a hot engine hard to start. Replacing or rebuilding the carburetor wouldn't solve anything because the real culprit is heat. What needs to be done here is to reroute the fuel line away from sources of heat (like the exhaust manifold and pipe), and/or to insulate the fuel line by fabricating aheat shield or wrapping the fuel line with insulation.

Hot start problems can also be caused by excessive resistance in a starter, poor battery cable connections, or a faulty ignition module that acts up when it overheats.​
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RidesWithYah said:
I'm not familiar with the exhaust manifold on a 250.
You wouldn't happen to have a heat riser stuck?
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I removed the flap in the heat riser before I put it back together. But thanks for the suggestion.
I have put everything back as it came from the factory and I'm beginning to think it could be flooding instead of starving for fuel when it will not start.
 
Someone once told me that fuel lines should slope up from the fuel pump to the carb, and that a level section was ok, but never to take them higher than the carb and back down. Anyone else heard that?

Yours goes up level with the top of the valve cover, then down to the carb. I'm not sure I understand why that might be the problem, but it might be worth a shot.
 
Nice looking engine compartment Fielddad.

fielddad said:
I'm beginning to think it could be flooding instead of starving for fuel when it will not start.
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Next time it does the "Hot Start" problem pull some plugs, if they are wet with fuel, you've uncovered another clue.

I'd be inclined to take a piece of 3/8" rubber fuel line, cut it with an x-acto knife down one side, and slip it over the fuel line from the distributor to the carb, secured with some hose clamps. Just wondering if perhaps it's getting heat soak really bad from the thermostat housing?
 
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Lakeroadster said:
Next time it does the "Hot Start" problem pull some plugs, if they are wet with fuel, you've uncovered another clue.
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Yesterday when working on the new problem it spit fuel back through the top of the carb when it would not start hot without any throttle at all after an extended crank and then tried to run backwards after I let off the starter.
 
RidesWithYah said:
Someone once told me that fuel lines should slope up from the fuel pump to the carb, and that a level section was ok, but never to take them higher than the carb and back down. Anyone else heard that?

Yours goes up level with the top of the valve cover, then down to the carb. I'm not sure I understand why that might be the problem, but it might be worth a shot.
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I actually moved the fuel line away from the valve cover to get it away from the heat, could be a issue I created. Never heard of that but I'm willing to try just about anything.
 
To tell whether it's a rich (flooding) or lean problem take a squirt bottle of gas and give about a half teaspoon shot into the carb before trying to crank hot. If it makes it worse it's a rich condition and if it makes it better it's a lean condition. I'd bet it's a rich condition but one just as well find out for sure. When an engine backfires through the carb it's has too lean a mixture or ignition/timing issues.
 
Did you say that you removed the heat riser flap internally? If so, you get hot exhaust air under your manifold all the time. In the 53, the only time it vapor locked, I found that the riser was stuck open, overheating the manifold.
 
After rereading all your posts on this nasty problem, I see no mention of the mechanical fuel pump and if you have tested it when everything is hot, if the starter slowed when cranking during these times, if you have looked into if the head gasket is still good, if you tried to pull start the truck when it is having this issue to see if it will start when moving. Great photos btw.
 
ccharr said:
After rereading all your posts on this nasty problem, I see no mention of the mechanical fuel pump and if you have tested it when everything is hot, if the starter slowed when cranking during these times, if you have looked into if the head gasket is still good, if you tried to pull start the truck when it is having this issue to see if it will start when moving. Great photos btw.
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I did a comp. test before I installed the engine about 300 miles back everything was good then so I assume it still is. My fuel pressure is at 3.7 PSI when hot and the engine cranks like a pro cold and hot. I'm running a PG tran so can't pull off. It has showed no signs of overheating at any time sine I have been driving it the past 3 months.
 
ol' chebby said:
Did you say that you removed the heat riser flap internally? If so, you get hot exhaust air under your manifold all the time. In the 53, the only time it vapor locked, I found that the riser was stuck open, overheating the manifold.
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Well just tried another experiment, started it let get to operating temp, shut off tried to restart, no luck, poured small amount of fuel down the carb, heard a boiling sound but it did start after the second dose of gas down the carb. I think the intake is so hot it's boiling the fuel and vapor locking. I pumped the carb a bunch while cranking enough to see gas running out on the intake and still no start, immediately pulled 2 spark plugs and they were dry. All this being said I think you might have hit on something about the heat riser allowing the intake to overheat. Now for my next delima is to find a good exhaust man. for a 72 250 that has a good heat riser flap and spring.
 
Update, I pulled the manifold and separated the exhaust from the intake and replaced the gasket with the solid one instead of the open one that allows heat to enter into the intake. I thought I had removed the damper flap when putting it back together a couple years ago but didn't so I freed it up and made sure it is completely open and locked it in that position. Today the intake temps are much cooler and the truck is starting much better so far but the so are the outside temps due to the rain and clouds. Before the manifold removal temps were 160F after they are 125F and the truck starts great. Forecast for the later part of the week are back to normal so the true test is yet to come. Thanks everyone for all the suggestions and response.
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ccharr said:
Your Welcome, btw, the truck really looks great.
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Yes Sir thank you for the direction on the exhaust, I hope when the weather warms back up we will be good to go. When people share their experiences with others much can be accomplished.
 
Lakeroadster said:
Off Topic Question: Is the silver truck and the maroon truck the same one?
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Yes it is, I painted the maroon when I was 15 in a high school ag shop. The Chevy has always been in the family since new. My grandfather sold it to me when I was in H.S. and I parked it from 1976 to 2011 in a garage then decided to get it back up and going again. I'm giving it to my sister this fall for her birthday as a surprise, she learned to drive in the ol 50 and so did my mom so it has a lot of special meaning in our family. That's why I need everything working exactly as it should. My next project is a 57 Belair 2 dr ht.
 
Thought I had the problem fixed but drove it today and could not get it started after it sat for about 10 mins. Outside temp was 93. Had to let it set for over an hour before it would start. So back to the drawing board:mad:
 
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