When cold, my stock 223 I-6 fires right up and runs great at normal op temp of 160. However after shutting down and trying restart after 10 minutes, it sometimes takes several to a whole bunch of rotations before she fires up again; generally I have to floor the gas pedal to get it to fire. Is this just one of those things I have to deal with? I'm ruling out the coil and condensor for I figured if they were going south, the truck would have died after warm-up. Weak points? I don't smell any fuel after shut down so I don't think the carb is leaking into the manifold. Appreciate any tips. Steve

 

Very likely the volatile gas we get these days is vaporizing in the fuel pump and in the line from the pump to the carb, and in the carb itself, after shutdown. There are similar problems with flat V8's. You can go to an electric pump and eliminate the temporary starvation, or put an electric to prime it but run off the mech pump. Is it less noticeable in winter?

 

I have a Holley 1904 glass bowl carb and since there is fuel already present, would an electric pump benefit? It pretty much behaves the same way once heat sink sets-in.

 

I assume the glass bowl is full enough to cover the jets?

You could have a weak coil then, or a condenser that is sensitive to heat, but you don't have problems once it's running?

See how it does if you just floor it before you even start cranking.

 

No problems during running so it doesn't seem to be a coil/condenser issue. I'll try flooring it before cranking and see what happens. Once she fires-up, everything is good to go.

 

I sounds like your engine is flooded. I have had this problem in warm weather with most of my carburetors since Texas started adding 10% alcohol to the gas. Flooring it allows lots of air to mix with the gasoline already in the intake, leaning out the mixture enough to let the engine start. I agree that if your spark was bad, your engine would likely run badly immediately after it starts. How full is the glass bowl when your engine is running? I adjust the float down so the fuel level never goes above the top of the little square cast into the glass bowl. That fixed the problem for me.

 

Here is a photo of my carb; from what you have shared it sounds like the float may be set too high. If so, is there a way to adjust without removing from the manifold?

 

Yes, that's way high. 38Coupe knows better than me how to adjust. The manual for these is also here: (for an IH but same) Holley 1904 Carb, 1953 IHC - The Old Car Manual Project

You could adjust it by trial and error by taking off the glass bowl and bending the lever.

Here's where 38 is saying to set it

 

Hey Steve,
I have exactly the same thing happening in hot & humid Texas & I'm running a totally modern Edelbrock 650cfm carb. I'll be curious if your fix works - this is on my list for next week.

Mine starts fine but if you go somewhere & then come out 10 minutes later - it's heck to start.

Ben in Austin
1950 F1 (351W/AOD)

 

38 Coupe's recommendation of adjusting the float level sure made a difference. I lucked out and got it adjusted right the first time (which usually doesn't happen) Here is a new photo with the gas line right on the top of the sqaure in the glass. I fired her up and let it get to op temp then shut it down for about 10-15 minutes. Flipped the key and she fired right up! Many thanks for everyone's inputs. Sorry about the dull photo. Steve

 

I just got your PM, sorry about the slow reply; looks like you got it all figured out. Glad things worked out for you.

Also thanks to Albuq F-1 for the great how-to graphic. Sometime a picture is worth a bunch of words.

I first started driving flatheads when I was in high school in the mid 1990s. I gladly set the float level on all my carburetor rebuilds to Ford's specifications with good results (except the carburetor with the porous casting, that was a pain to figure out).

Since the introduction of alcohol laden gasoline I have had to lower the floats quite a bit. My first experience was with the Stromberg 97 on my 37 sedan. I rebuilt that carburetor to spec and it ran great. It would flood in about 10 minutes after shutting the car off (I was doing this work in a friends driveway in San Antonio). We took the air cleaner off and watched. About 5 minutes after shutting the engine off gasoline would start dripping from the discharge nozzles down the venturis. The alcohol laden gas won't "float" a float as well as pure gasoline, and it expands more when it heats up. Combine the two and you have a sure fire engine flooder every time. I have taken to setting the floats down about 1/2 inch in every carburetor I rebuild, then fine tuning from there.

For example, the first time I set the float on my 53 sedan in 2001 the gasoline was about 2/3 the way up the float. Now the gasoline is about all the way up the float just like Steves55 pictures show.

Sorry for the long post, but I thought I should explain my reasoning.

 

Now that it's strating to really warm up in Florida, I will take her out and see how it goes. Between the 1/2 inch carb spacer and the float adjustment, I think I will be good to go. I also drive a flathead (46 Ford Coupe) a lot and may have to look at the float adjustment on the Holley 94. I don't have any problems with warm start ups but if I go up a steep hill or overpass, sometimes she will stall and surge. Not sure of it's vapor lock or float needing adjustment. Thanks again to you and Ross for the help. Steve