Sorry this a bit long but I gotta say it all to figure out where I went wrong.
this is my second project my first was 72 mustang with 429 it was a hole lot of fun but I didn't do my own engine work I learned what I could at the time but I did pay a fella to rebuild it and I bought a new carb for that. I did all the rest.
This is my current project and im determined to do it all myself waste no part of the experience and I want to be more capable.
I bought this 86 chevy 4x4 with a 350 small I believe it to be. I drove it home but it had absolutely no power almost was just barely making highway speed and actually lost speed in third gear standard by the way it developed a backfire out the carb it got real bad to the point I couldn't get it to drive very far it had no power to move itself very easily I couldn't even get it up the front lawn into the back yard for the winter so that's where it sat. Also this backfire was only when I gave it gas of any sort and it was like 2 second if not faster between backfires, idled and started perfect.
So this year ive gotten to work on it and have looked into so many things and gotten right into this thing. I asked around about my problem and one fella suggested a bent rod made me cringe at the thought cuz I don't know how to change that Anyways another guy suggested carbon tracking in the distributor and of corse aguy suggested the timing. All relative theory's so I decided to make a list and work my way down. I started with the distributor cap, I checked for tracking and didn't see anything out of place was pretty clean and un warn, but just to be safe I changed the cap rotor and I also put a bigger new coil on it. The problem hadn't changed so next I decided to play with the timing I played with it for some time didn't matter what I did it made no change what's so ever besides making it slower backfires with the slower engine speed. So thought well I have no idea how old the fuel filter is so I went out bought one it was extremely small but it was the right one and the old one wasn't dirty but was tattered real good. when I changed the filter,backfire was gone. Except now I had fuel coming out the top of the carb and leaking over the side I was worried I was gonna have a fire if I ran it too long. it seemed to be coming mainly form the exelorater pump chaft that comes up. So I asked a guy what he though when I told him about it he said that's easy part of my old filter was stuck in the needle I wasn't sure what needle I though perhaps he meant the needle in the jets but he said just take the fuel line off the carb and run it out of fuel and put it back on. Easy enough I tried it and it worked the fuel stopped coming out the carb but my backfire came right back exactly the same as it was before. So I gave it some good thought and decided I should look into changing that exelorator pump. Si decide I would just rebuild the whole carb the kit only cost 40 something why not a learning experience my first one. Its a quadrajet 7080292 I believe, pretty basic unit. I spent the next day carefully rebuilding this carb and found my power piston assembly was completely stuck I didn't even know it was a piston till I finally got it out and saw the spring underneath the thing and noticed how it works.
Now my first question is that there was a set point set screw right behind the power piston toward front of the carb I grabbed it with my plyers and then realised what it was and tried to put it back to its original position but wasn't realy sure. It mentions nothing about it in my rebuild kit and when the carb is back together there is no getting at it. I have no idea what its for dose anybody know?
I continued my build till I was finished and had everything back together nicely changed that accelerator pump and everything that was in my kit well that applied to my carb. I put it back on the truck and started it up it idles good but now when I give it any sort of gas it either dies or I can get it to slowly rev up but it gives off a poof of fuel like there is way to much and a few times it was a ball of fire and its not loud when it dose it. and after giving it gas it will always die there is no letting off slowly back to idle it will always shut off. granted the first time the choke as too far closed so I adjusted it it open further and further yet till it was wide open no difference. If you can see what I forgot to do or perhaps and obvious tell tale sign as to what's still needed any input or suggestion's would be helpful. oh and its new fuel
this is my second project my first was 72 mustang with 429 it was a hole lot of fun but I didn't do my own engine work I learned what I could at the time but I did pay a fella to rebuild it and I bought a new carb for that. I did all the rest.
This is my current project and im determined to do it all myself waste no part of the experience and I want to be more capable.
I bought this 86 chevy 4x4 with a 350 small I believe it to be. I drove it home but it had absolutely no power almost was just barely making highway speed and actually lost speed in third gear standard by the way it developed a backfire out the carb it got real bad to the point I couldn't get it to drive very far it had no power to move itself very easily I couldn't even get it up the front lawn into the back yard for the winter so that's where it sat. Also this backfire was only when I gave it gas of any sort and it was like 2 second if not faster between backfires, idled and started perfect.
So this year ive gotten to work on it and have looked into so many things and gotten right into this thing. I asked around about my problem and one fella suggested a bent rod made me cringe at the thought cuz I don't know how to change that Anyways another guy suggested carbon tracking in the distributor and of corse aguy suggested the timing. All relative theory's so I decided to make a list and work my way down. I started with the distributor cap, I checked for tracking and didn't see anything out of place was pretty clean and un warn, but just to be safe I changed the cap rotor and I also put a bigger new coil on it. The problem hadn't changed so next I decided to play with the timing I played with it for some time didn't matter what I did it made no change what's so ever besides making it slower backfires with the slower engine speed. So thought well I have no idea how old the fuel filter is so I went out bought one it was extremely small but it was the right one and the old one wasn't dirty but was tattered real good. when I changed the filter,backfire was gone. Except now I had fuel coming out the top of the carb and leaking over the side I was worried I was gonna have a fire if I ran it too long. it seemed to be coming mainly form the exelorater pump chaft that comes up. So I asked a guy what he though when I told him about it he said that's easy part of my old filter was stuck in the needle I wasn't sure what needle I though perhaps he meant the needle in the jets but he said just take the fuel line off the carb and run it out of fuel and put it back on. Easy enough I tried it and it worked the fuel stopped coming out the carb but my backfire came right back exactly the same as it was before. So I gave it some good thought and decided I should look into changing that exelorator pump. Si decide I would just rebuild the whole carb the kit only cost 40 something why not a learning experience my first one. Its a quadrajet 7080292 I believe, pretty basic unit. I spent the next day carefully rebuilding this carb and found my power piston assembly was completely stuck I didn't even know it was a piston till I finally got it out and saw the spring underneath the thing and noticed how it works.
Now my first question is that there was a set point set screw right behind the power piston toward front of the carb I grabbed it with my plyers and then realised what it was and tried to put it back to its original position but wasn't realy sure. It mentions nothing about it in my rebuild kit and when the carb is back together there is no getting at it. I have no idea what its for dose anybody know?
I continued my build till I was finished and had everything back together nicely changed that accelerator pump and everything that was in my kit well that applied to my carb. I put it back on the truck and started it up it idles good but now when I give it any sort of gas it either dies or I can get it to slowly rev up but it gives off a poof of fuel like there is way to much and a few times it was a ball of fire and its not loud when it dose it. and after giving it gas it will always die there is no letting off slowly back to idle it will always shut off. granted the first time the choke as too far closed so I adjusted it it open further and further yet till it was wide open no difference. If you can see what I forgot to do or perhaps and obvious tell tale sign as to what's still needed any input or suggestion's would be helpful. oh and its new fuel