Hard start when warmed up.
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Hard start when warmed up.
72 f100 360/435/d21. Has a recently replaced/rebuilt mc 2100 with the thermo.tube choke. It takes 2 tries to start, 2 pumps then crank. It'll catch then die. 2 more pumps then catch and I have to hold the go pedal for a a few second then it will warm up just fine. I can drive it around just fine and it will restart as long as it doesn't sit too long. I have owned a few 2100's 0ver the years and I never had a restart issue. this rig likes no throttle at restart where all my other ones liked to crank then a pump to fire when warm. So if it sits for more than a half hour when warm I have hold the skinny pedal to floor and let it crank for about 5 to 10 seconds. I don't like to work the starter like this and I would prefer to not dump so much fuel into the engine for a restart. Any help would be great. thanks, Joe
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Joined: Jul 2003
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From: Las Vegas
jodaddy,
Actually, when you hold the zoom pedal to the floor,
you are not putting gas into it so much (except for the initial accelerator pump squirt) as you are letting in more air to combat an over-rich/flooding issue or vapor lock. This might be caused by carb "boiling over" from heat after shut off. Try pulling the air filter cover when you shut it off warm and keep an eye on it for the first 10-20 minutes to see if gas is still pouring/leaking into the intake manifold.You might also want to check points, condenser and timing, as if they are not right, warm start problems can occur. You didn't say where you are located, but I have a similar setup in Las Vegas (110+ degrees) heat and have to be wary when starting warm.
HTH,
Gene
Actually, when you hold the zoom pedal to the floor,
you are not putting gas into it so much (except for the initial accelerator pump squirt) as you are letting in more air to combat an over-rich/flooding issue or vapor lock. This might be caused by carb "boiling over" from heat after shut off. Try pulling the air filter cover when you shut it off warm and keep an eye on it for the first 10-20 minutes to see if gas is still pouring/leaking into the intake manifold.You might also want to check points, condenser and timing, as if they are not right, warm start problems can occur. You didn't say where you are located, but I have a similar setup in Las Vegas (110+ degrees) heat and have to be wary when starting warm.
HTH,
Gene
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From: Big Sky Country
That was my first thought as well, if this is the case a phelonic carb spacer will remedy that.
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I live in western MT at about 3000ft. Not quite like vegas heat but lately in the 90's. I do have one of those spacers. I think my truck came factory with some sort of cold weather package because it has a non functional block heater and water hose going through the spacer. I just noticed the water hose this morning after I posted. I pulled the hose and routed it back into the engine. It might have helped a little but not the cure all. the fuel in the bowl does get hot. I noticed that when I was changing jets a few weeks ago. timing is within a degree or 2. I guess I better wipe the dust off the dwell meter.
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Good guess. If you're really psychic tell me what street i live on and I'll buy you a six pack. Dwell angle was out of spec by 4 0r 5 degrees. Hopefully that's the culprit. So the air gap is what sets the dwell angle? I haven't really messed with a points dizzy for over a decade until I bought this truck. Thanks for the help. Joe
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From: Big Sky Country
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From: nevada
more octane
My 390 likes a little more octane in the desert heat. i could knock the timing back a few degrees too, but I like the way it runs with some advance. Pulling the boat in 110 degrees will make it ping a little if I dont run at least mid grade or add a booster. In the winter it will drink anything. Once had to pour a gallon of coleman fuel in the tank to get home. Got me the 10 m I needed.Getting rid of the carb spacer with the hose helped too, had a 1" spacer with the 2 bbl, but now the 4bbl has a thinner one.
