79 20R won't start. Narrowed down to carb issue. prob.
06-20-2009, 05:53 PM
#1
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79 20R won't start. Narrowed down to carb issue. prob.
Finally got my '79 pickup all back together, running great, went got my own insurance, and "bought" it off my dad. So now its all legal, and wont start.
Narrowed it down and the inline elec. fuel pump was culprit. Ordered a new one, put it on with 2 fuel filters (before and after pump). Still wont start!
It will start if gas is poured into the carb, and will stay running with my foot on the gas anywhere over 1500 RPM. Will not idle.
Played with the idle screw and mixture got it to idle, and run perfect. Drove it and it died. I'm not putting fuel to the carb.
Today I played with the whole system and I know the pump IS pumping fuel to the carb from the tank. But it wont go into the carb for start up.
I did nothing other than get it insured and put plates on it from the time it was running fine around out back, till now its not starting. Vac lines are mostly plugged off and open, BUT, it was running like this for more than 3 years, so it can not be a vacuum issue.
Any carb guys wanna point me in the right direction?
Narrowed it down and the inline elec. fuel pump was culprit. Ordered a new one, put it on with 2 fuel filters (before and after pump). Still wont start!
It will start if gas is poured into the carb, and will stay running with my foot on the gas anywhere over 1500 RPM. Will not idle.
Played with the idle screw and mixture got it to idle, and run perfect. Drove it and it died. I'm not putting fuel to the carb.
Today I played with the whole system and I know the pump IS pumping fuel to the carb from the tank. But it wont go into the carb for start up.
I did nothing other than get it insured and put plates on it from the time it was running fine around out back, till now its not starting. Vac lines are mostly plugged off and open, BUT, it was running like this for more than 3 years, so it can not be a vacuum issue.
Any carb guys wanna point me in the right direction?
06-20-2009, 06:05 PM
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take the top of the carb off and blow out the bowl and floats and all the little passages, this was happening to mine and thats what i did and it worked like a top
06-20-2009, 06:19 PM
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Sorry for my newbyness to working on carbs, but when I crack the top off the carb, is it really safe to use compressed air to blow out the passages? Aren't all the little do-dads in there delicate?
06-20-2009, 06:46 PM
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if you pull off the top of the carb, then all the little do dads are still at the top, cause the floats and everything are on the top, so theres nothing to get blown away on the bottom. and to do the top, take the float and needle valve out and then blow all that out. easy a 123
06-21-2009, 06:34 AM
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Took the top of the carb off, noticed the power valve spring was sticking in the bowl....freed that up, put it back together, and she fired up and idled rough.
Gave it gas, and she died, and now I'm back at square one with the same problems...
Gave it gas, and she died, and now I'm back at square one with the same problems...
06-21-2009, 09:23 AM
#7
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did you rebuild the carb?
if you did not i would do a rebuild/ full cleaning. check the float and see if it is cracked, and see if it is w/in speck of lift/drop for the needle valve. also check the needle valve for gack etc... my old 20r carb had a bunch of crap built up on the needle and would cause it to stall and starve of fuel.
where is the fuel level in your sight glass?
if you did not i would do a rebuild/ full cleaning. check the float and see if it is cracked, and see if it is w/in speck of lift/drop for the needle valve. also check the needle valve for gack etc... my old 20r carb had a bunch of crap built up on the needle and would cause it to stall and starve of fuel.
where is the fuel level in your sight glass?
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06-21-2009, 03:54 PM
#8
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did not rebuild the carb.
Took the top off again a cleaned the bajesus out of the bowl, blew out the jets, cleaned the float. Fired up first crack.....still wouldn't hold an idle, played with the idel some more and got her running nice. Then i give it gas and she stalled and again, I'm back to square one.
Fuel level is right in the middle of the sight glass
Took the top off again a cleaned the bajesus out of the bowl, blew out the jets, cleaned the float. Fired up first crack.....still wouldn't hold an idle, played with the idel some more and got her running nice. Then i give it gas and she stalled and again, I'm back to square one.
Fuel level is right in the middle of the sight glass
06-21-2009, 05:31 PM
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could it jump 180* all by its lonesome?
Runs like a champ with my foot on the pedal from 1500-5000
Foot off it idles (*sometimes*) at a reasonable 800-900
Randomly dies and then wont start between the 0-1500 range with my foot out of the throttle
06-21-2009, 07:20 PM
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i'm having the same issue with mine, it turned out to be a pinched fuel line between the pump and carb, you might want to check that....it took me about 30 min and a almost dead battery to stumble across it
06-21-2009, 07:42 PM
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if you got fuel in the bowl. u can try a clear flood. takes 2 people. get someone inside to start it. u under hood. get the rpms up to about 2000. cup your hand over the throat of carb basically choking it out. release your hand and get it to run smooth do this at least 3 times.. oh have u checked to c if your anti diesel solenoid is funtioning. that would make it not idle.
its a screw in piece with a red or black single wire coming off of it pull and check that it clicks and moves with key cycled on and off
its a screw in piece with a red or black single wire coming off of it pull and check that it clicks and moves with key cycled on and off
06-21-2009, 07:59 PM
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i did have an issue with my accelerator pump getting clogged and wouldnt shoot fuel into the intake so u can look into the carb and pump the accelerator c if it does. have fun make friends 
06-21-2009, 08:12 PM
#19
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i'll be pulling it off tomorrow, and probably p/u a rebuild kit from napa
30 year old carb...probably never rebuilt, probably needs one lol
30 year old carb...probably never rebuilt, probably needs one lol
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