73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: timthescarrd on November 29, 2011, 11:33:10 am
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Been having some issues with hot-starting. Truck is an '83 K10 with a sbc350 and 700r4. It has been swapped to a non-CC quadra-jet. On a cold start, one push of the gas and she'll usually fire right up, but sometimes when my wife goes to start it hot, it won't start and floods (not all the time). I can get it to start when it does this by pushing down of the Fast Idle cam so that it locks the throttle plate open, then just turn the key and she'll fire up and run fine.
I'm thinking that either the choke pull-off is bad or the electronic choke thermostat is closing to quick, but it doesn't always do it. It also seems to happen at different ambient temps, I've noticed it anywhere from 35F outside temp to 53F outside temp (it's been pretty cold here of late).
Any thoughts are greatly appreciated.
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Mine on my 74 was doing the same thing before I rebuilt it. I think my problem was the venture's in my carb. were some what dirty. So when it was cold it would fire right up, when I got it warm or hot, it would sometimes act just like you described.
After the rebuild, now one pump when cold starts right up, when warm, all I have to do is turn the key and fires up every time. Not once since rebuild on carb. has it hesitated when warmed up.
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i have this problem on my toyota 4 runner that i have a 350 chev V8 in it with edelbrock 600 carb.
anyways the only quick way to start it is to push the gas pedal all the way down
and keep it down until it starts.
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If I try holding the gas to the floor, it will start and stay at low RPM's and billow nice black gas-scented smoke out the tailpipe, and will stay running as long as the pedal is to the floor, but if i let off even to half it dies
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I have a wizard here locally with carb's, let me print this out today and ask him, I will try to post tonight what he said.
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sounds like the float is stuck or the fuel pump is not reliving pressure over filling the bowl.
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If I've got this right, the choke pulloff doesn't do anything until just after it starts and builds a little vacuum, so I'd cross that off the list. The choke heater in an electric choke isn't electronic, it just heats the coil to open the choke fully after it has had voltage to it for a few minutes. This could certainly be the problem. When the engine has been running long enough to heat up, 10 minutes or so, your choke should be open fully. You can move the accellerator linkage to make sure it doesn't snap back closed again. The fact that it helps to open the choke is a sign. Start the engine and put a voltmeter lead on ground and the other on the wire to the electric choke and see if you have voltage. Another possibility is someone has just cranked the black dial (choke adjustment) way too rich--closed too tightly and it can't open fully.
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When I got the truck I replaced the choke thermostat and ran a brand new wire to it. I know it is getting voltage, and it starts beautifully every morning. It may be that it is to rich, but it does seem to open fully
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If I try holding the gas to the floor, it will start and stay at low RPM's and billow nice black gas-scented smoke out the tailpipe, and will stay running as long as the pedal is to the floor, but if i let off even to half it dies
I had similar symptoms on my 81. It would cold start fine. If I shut it off for a couple seconds it would still start fine. But if I let it sit for more than a minute, it would flood out. I went through the choke and ended up putting in a manual choke to eliminate all doubt with that, yet the problem still persisted. It ended up being heat soak from the engine. The carb would get hot enough that fuel would boil over in the float bowl and dump gas into the engine thus flooding it. I installed a thin stamped steel heat shield between the carb and carb gasket which assisted in dissipating the heat. I haven't had any hot start problems since.
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That sounds eactly like what happens, but its random... the worst part is it never does it to me, only my wife :(
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Maybe your wife is flooding the carb on accident? My moms jeep has a 360 v8 with an edel 600 and it load up pretty bad. I have to hold the pedal in a certain amount and get it started thwn I have to hold it for a while. It pukes black smoke, and I have to clear it all out before it will idlr.
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That sounds eactly like what happens, but its random... the worst part is it never does it to me, only my wife :(
In my business that is referred to as operator error. Or at least you know your truck likes you the best. ;D
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You might have a heat soke problem. I had the same issue until I installed a carb spacer. Todays gasoline has a high mixture of methonal which has a quicker evaperation rate.
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I keep suggesting user error and she swears she isn't, and it's actually her truck. Looks like I may need to try a carb spacer.
We didn't have the problem this summer, it's only been since maybe october, could it be the weather?
Where do I get a carb spacer and is there anything i should look for in one?
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So, why don't you watch her start it up to see what she does? Maybe she just wants a NEW one.... ;D
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On a cold start, i jab the throttle once to set the choke, then it fires within a full revolution. Once warm, I never have to touch the throttle to start it, it'll fire right up.
Could it be that you, or your wife, don't need to touch the throttle before a warm start attempt? Just throwing it out there. Every carbed vehicle i've ever had, had it's own little quirk when starting. Even my boat does. Once figured out it fires right up too.
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I know I don't hit the throttle on hot start. And she swears she isn't either. The problem as she describes it is it does start for a few seconds, long enough to put on her seatbelt then dies and won't restart without choke intervention. It will also give a little smoke if you rev the engine pretty good while parked. So I think I may have a combo of heatsoak and too rich. She's an old truck with plenty of problems but she goes good when she goes
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Check the choke operation, check for leaking well plugs, check the pick up coil.
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vile whats a well plug?
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If I'm not wrong, well plugs are the notorious little plugs on the bottom of quadrajets known to begin leaking and dropping extra fuel into the intake. common fix is to epoxy 'em during a rebuild, best fix is to drill and tap them and then twist in a plug. Not sure what the pick up coil is though?
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didnt know that was the name for them. but the pick-up coil is under the rotor in the distributor you have to remove the distributor then remove the pin in the gear then slide the shaft out this will expose the pickup coil at the base of the distributor
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Several company's offer carb spacers, do a internet search, then pick which one suits your needs and the needs of your state laws.
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why a spacer?