85 305 chevy automatic

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  #1  
Old 10-10-09, 05:59 PM
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85 305 chevy automatic

Hi guys i was in my truck the other day when i give it gas it bogs down and sputters and wont gain rpm unless you have it held to the floor. that was the first time it happend then it started to run fine. now it is doing it again put now its way worse it will idle if you dont give it any gas put as soon as you give it gas it smokes... listening to the motor it sounds like it is running good but go and listen to the exhaust its cutting out. soon as i put it in to drive to go it floods out and dies any suggestion please help just bought this truck a month ago and has ran awsome up to now.. it just started when it got cold here in kansas let me know what you think
 
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  #2  
Old 10-10-09, 06:08 PM
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Sounds like a carb problem to me, maybe a choke pull off or choke thermostat.
 

Last edited by wire twister; 10-10-09 at 06:08 PM. Reason: typo
  #3  
Old 10-10-09, 06:12 PM
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Thats kind of what i was thinking what can i do take the carb off and clean it.. looking for the cheapest way would like a new put cant afford it
 
  #4  
Old 10-10-09, 07:22 PM
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I think wiretwister is right,, & the parts are cheep & you don't take the carb off even... You'll need some vacuum hose to put on the choke pull off port & suck on it with your mouth, (unless you have a vacuum pump).. Does the pull off open the choke slightly (must be choked @ this step)) If so does it hold the vacuum with your tung plugging the end of the hose??? If not, it needs replaced & remember to properly adjust it... Roger
 
  #5  
Old 10-10-09, 09:15 PM
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ok Thank you for all your help guys i will let you know tomorrow if this is what is wrong.. i agree with both of you i dont know much about them but i will give it a try tomorrow thanks again
 
  #6  
Old 10-10-09, 09:50 PM
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Well i do know that this carb is worn out i just got off the phone with my dad and he has a 87 chevy that he told me he would give me the carb off of it.. now his motor is a stock 350 will this fit on my 305 with out a whole lot of work can i just simply bolt it on and good to go thanks
 
  #7  
Old 10-11-09, 04:41 PM
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you think it will bolt right up
 
  #8  
Old 10-11-09, 05:23 PM
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It only took 35 mins for you to go from fixing it to totally worn out??? Wow,, your good..Haven't a clue... 2 or 4 barrell?? is the Jetting the same (I'm thinking not).. I never was a Chevy Man, I just fixed what was on them... If you want to change stuff without fixing anything,, you'll have to wait for others... Sorry,, Roger
 
  #9  
Old 10-11-09, 05:40 PM
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lol no i have known for a while that it is worn out i dont know much about carbs and i have not fixed it yet i was just going to put a differnt carb on it and replace it all at once or just put a new choke pull off in and choke thermostate i dont know much about them was wondering witch way you would go this truck ran great in the summer now that it is cold it will start and you have to floor it for it to stay running and then it just floods and barly runs.. never can get it warmed up im sure if it was warm out it would run fine always has till this cold spell came. im pretty sure it a two barrell
 
  #10  
Old 10-11-09, 05:52 PM
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More than likely it is a 4 barrel carb. The one off the 350 should bolt right on and run fine, if it is in good shape. Quadrajets are (were) bad about wearing around the throttle shafts. This usually causes a driveability issue, mainly they wont idle down because of vacuum leaking around the shaft. Barring this the jetting should be close, if not the same, be aware you could still have a choke thermostat or choke pull off problem with this carb as well, but it is worth a shot.
 
  #11  
Old 10-11-09, 05:57 PM
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ok thank you and you are right i just looked on the internet it is a 4 barrell and it does have idle problems i think i will take a shot and put my dads carb on my truck he did tell me on his carb you have to poor gas in it to start the truck it is on now put he said its something with the primer that he thinks would be easy to fix now he knows about as much as me when it comes to carbs so that is not very much.. i know i have a lot of questions thanks for helping me out
 
  #12  
Old 10-11-09, 07:46 PM
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the choke is electric on that carb and should start opening within 30seconds of starting, if the truck started and ran fine when the weather was warm but now you have to floor it to keep it running you probably have a problem with either the vac brake on the carb gone bad or your float is adsorbing fuel and starting to get heavy. with the air breather off and the engine cold(not having been started for at least 4hrs) look at the carb, if the top flap is shut, have someone start the engine, make sure your hands aren't close to any moving parts like belts or the fan, watch the choke it should imediatly open about 1/4-in, if it doesn't open as soon as the engine starts your vac break is bad or the hose to it is bad, next time the opening of the choke it should open fully in about 5 minutes, if it doesn't check for 12volts to the heater element, if none your oil pressure switch may be bad, the switch is to keep the element from heating up and opening without the engine running. if the choke opens correctly and the problem persists you will need a carb rebuild and the float replaced. that would be preferrable to the swap, because the description you have given is that the choke is not working properly on that one either.
 
  #13  
Old 10-12-09, 02:29 AM
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ok thank for your response i think i will put my dads carb on now for my question if i take my dads carb complete with every thing including the all the choke stuff i can just simply hook all the vacum hoses up where they need to be put the gas line to it bolt it done and should be fine right... the carb i am putting on there has to be primed but better than the one i got.. It sure makes my dads truck run good besides the priming part but i will live with that thanks let me know if i am on the right track here..
 
  #14  
Old 10-12-09, 07:45 AM
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carburetor

The 87 should be fuel injected. If it was a carry over from 86 it will have some electrical components on it that your 85 probably didnt have,thus no wiring for it. I would rebuild the one you have. Stay with stock and eliminate problems.
 
  #15  
Old 10-12-09, 03:17 PM
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First half year of 87 should be identical to the 85. Fuel injection did not start until the last half of 87.
 
  #16  
Old 10-12-09, 06:09 PM
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ok guys before i was gonna tear into this carb and replace it i just got inside from tinkering with it and here is what happend and what i did.. ok i started the truck would barley idel i open the choke plate 1/8 of an inch runs good until you gun it then it closes the choke plate i do not the choke is not working so i bent the choke pull off rod to hold it open 1/8 of an inch now it will start and run fine... i even waited a couple hours for it to cool back off and now it is starting and NOT sputtering running great.. with just simply adjusting the linkiage .... now my question is the choke pull off does not work i just modified it by the linkage should this be alright.. thanks for hangin in there with me guys any comment would help thanks a million
 
  #17  
Old 10-12-09, 07:36 PM
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you didn't try any of my suggestions to test the choke, however what you did tells me that two things are going on, one your choke pull off/vac break is not working, two your choke is not heating up and opening, you need to find out if the reason for not heating is lack of voltage or bad choke heater, most likely is the heater on that old of a vehicle. you can jumper from the batt positive to the choke heater and see if it opens, should open in about 1 min. if not you will need a new choke heater the old one is held on with pop rivets but I always tap the holes and install screws when servicing those carbs to make adjustments and replacement easier.

are you going to cowboy up or just lay there and bleed?
 
  #18  
Old 10-13-09, 04:26 AM
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I agree with the wrench, replace the choke thermostat, and the choke pull off. This should fix the troubles, better to fix the factory carb than to try to mollyhock it.
 
  #19  
Old 10-13-09, 10:25 AM
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ok i did take your advise i did the vacum test on the choke pull off and it holds vacum so i think its the choke thermostate now the choke thermostate has a wire going to it that is broke off i tried to hook it back up but the clip on the choke thermostate is busted i take it that is my problem.. i take this wire is the electric part of the choke correct me if i am wrong thanks a lot guys i am getting closer..
 
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