When I start my truck when it is cold it fires right up on the first hit. No prodding needed. And it runs like a champ. But when it is hot like today in the 90s it sometimes has a bit of cranking before it will fire. Is this common for very hot days? I do not have a fan shroud on it. I ordered one from Dennis Carpenter bit it does not fit and will return it. I will have to fabricate one somehow. Is it the heat that is causing hesitation?

Thanks for any suggestions.

Is the carb old?...maybe fuel sneaking by and causing a partial flood?

Choke hanging up?

You know, that is a good question and I will look into that. The choke may be hanging up. It is a nearly new carb and very clean but that does not rule out a possible mechanical issue. Thanks for the suggestion!

Check your air cleaner stud to make sure that it's not blocking your choke closed, I had that happen on my 78 F-150. So I had adjusted that by turning it a little to free up my choke plate, and I had shot some choke cleaner at it. Also check your fuel lines to make sure that they're not kinked or pinched.:

i haven't run many carbed engines on any regular basis so i dont know but i'm very interested in the answer!!! My truck does the same thing on 90F+ days, other then that a key bump cold or warm will fire her right off. i've been thinking the fuel boils off in the boosters and it takes little bit to get everything flowing again, vapor lock?. my truck runs about 190F at 90F and 200f at 98F, when my engines that warm pump shot almost instantaneously boils off the throttle plates, when i blip the throttle with the engine off.

just ranting again.

Something I've seen on my '78 on a hot day, is that that the EGR temp sensor for vacuum will be already be open on a hot day when I start the engine, causing it to idle very poorly. When I bought the truck, the temp sensor on the thermostat housing was set to kick in at 85 deg F. The sensor is color coded and be purchased for different temps. I replaced it with a 135 deg sensor, which helped a lot.

On a really hot day, the truck still idles poorly when starting, because there are exhaust gases already being dumped into the intake at startup. On a cooler day, the engine can warm up before the EGR valve opens, which is less of a problem.

If the EGR has been blocked off, which is typical, then never mind.

Fan shroud only keeps it from overheating, by pulling air through the radiator, so that will not have any effect on starting

Doug is spot on, that is probably the cure

You could also try not touching the gas pedal when starting hot, it might be prone to flooding. Your float level might be set a bit high.