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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1badchevy on July 02, 2016, 10:53:31 am
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Hi
I have a 350 4bbl. w/ stock dual tanks
It starts up just fine if I do it daily but if I let it sit for a couple days even pumping the gas pedal doesn't start it, I have to dump some gas in the carb.
I want to learn how to work on my own truck but don't know where to start.
Thanks
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You may have a weak fuel pump that bleeds the fuel backwards after a while of sitting. One of my trucks does the same thing.
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You may have a weak fuel pump that bleeds the fuel backwards after a while of sitting. One of my trucks does the same thing.
Thanks, that's where I was thinking of starting but wanted some advice from the forum first
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Or the plugs on the bottom of the carb may be leaking.....
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Or the plugs on the bottom of the carb may be leaking.....
Thanks, I will post the cause when I get it fixed.
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Same thing here. The fuel leaks back. I crank the engine (no throttle) for about 10 seconds to pump the float bowls up. Then I push the throttle to the floor and hold it there for a couple seconds, twice, then it will start on the first crank.
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The Q-jet carb bowl only holds a small amount of gas. The gas evaporates in a few days so you have to fill the bowl again. I recommend crank it for 1-2 seconds and the fuel pump makes a stroke and the gas will start to flow. Let it sit for 5 seconds and then crank for 1-2 seconds(save the battery & starter) About 3 or 4 times you can pump it and it'll start if the fuel pump is OK and the accelerator pump is OK. The fuel pump can be OK but If the choke doesn't close and the accelerator pump doesn't work it may not start without pouring gas in the carb.
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The Q-jet carb bowl only holds a small amount of gas. The gas evaporates in a few days so you have to fill the bowl again. I recommend crank it for 1-2 seconds and the fuel pump makes a stroke and the gas will start to flow. Let it sit for 5 seconds and then crank for 1-2 seconds(save the battery & starter) About 3 or 4 times you can pump it and it'll start if the fuel pump is OK and the accelerator pump is OK. The fuel pump can be OK but If the choke doesn't close and the accelerator pump doesn't work it may not start without pouring gas in the carb.
Actually, yeah, this too.
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Quad should fill up and start within 15 seconds or so with a good fuel pump.
Possible your needle is sticking when the bowl is dry.
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Quad should fill up and start within 15 seconds or so with a good fuel pump.
Possible your needle is sticking when the bowl is dry.
I tried the suggestions on how to get it to start and it didn't work so I will take a look in the carb, I have work on motorcycle carbs but never autos so this should be interesting.
Once I get this pickup started man it just purrs and starts with easy as long as I don't let it go for more than a couple days.
The pickup came off a huge ranch in southern New Mexico and is totally and I mean totally rust free, all the bolts came off so easy.
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Check u tube for videos on rebuilding the quad. Lots of info out there.
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R U putting fuel down the barrels of the carb or in the float bowl when it starts.
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R U putting fuel down the barrels of the carb or in the float bowl when it starts.
down the barrels
thanks for the tip on Youtube
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More than likely the fuel bowl is draining past the fuel well plugs. Fuel well plug repair kits are available, but provide marginal results. For the best long-term results you will need to lightly seat, peen, burnish and epoxy the plugs. Though pricey, the most durable epoxy for the purpose is Devcon Plastic Steel. JB Weld will also work if the metal is properly prepped, but JB Weld doesn't provide the longevity of Devcon. You should also install a pleated paper fuel filter that sports an integral check valve. The check valve serves a dual purpose. It prevents fuel in the tank and lines from draining through the carburetor in the event of a rollover, but also prevents overnight siphoning of fuel from the carburetor and lines back into the tank. As before, Youtube the procedure for sealing QJ fuel well plugs.
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If your well plugs are leaking badly you will experience hot start problems as well as a quickly dry fuel bowl.
I install a well plug kit in my own carbs and still have a dry bowl after a few days from heat and today's Ethanol enhanced fuels.
Regardless, after a few days of sitting cranking and several pumps of the pedal the carb should fill with fuel and start.
Otherwise it runs great, puzzles me.
If the accelerator pump in the carb was not working that would not be the case.
When you take the top off the carb don't miss the two screws inside below the choke flap.
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Thank you all, now I just need a day off from work :)
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Ok I have my pickup running perfect but it was a learning experience.
In my original post I said that I had to poor some gas in the carb if the pickup sat for more than a few days.
After having the carb rebuilt it wouldn't start and run at all so I turned the motor over with the gas line off after and before the gas filter and no gas was coming thru from the pump. The pump looked like it was pretty new but they only cost $18 and looked like it would be pretty easy to replace.
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OOPS hit the wrong key
Anyway changing the fuel pump is not too hard except if it is your first time, took me hours.
When I had the pump off I noticed that no gas was running out of the gas line from the tank so I blew air up the gas line and gas started running out. Got the pump hook up and after a couple tries the motor started up and runs/idles perfect.
Man am I a happy camper.
Thanks to all
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That's a good looking truck man!
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Thanks, it's my 3rd short box stepside, first one was a brown 1978 that I bought brand new in Howell Mi.. Second was a black 1979 bought in 1995 w/29,000 miles when I lived in Albuquerque NM. This blue 78 I bought from a classic car dealer and had to pay WAY OVER book. It came off a huge ranch in southern NM. and was never driven on the road, title says it has 2800 original miles but it's 102,800 miles. It has been very well maintained, it is totally complete right down to the spare tire jack in the engine compartment and it is TOTALLY rust free, the bolts come off so easy.
OBTW, all three pickups were 350 4bbl 4 speeds with the little chrome rear view mirrors. I wish this one was a automatic but you really only have to shift twice on the hwy.
It now has chrome bumpers :)
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Beautiful truck
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Yup, nice stock look., clean.
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Not sure what the status is, but have you tried holding the gas pedal down? Got an update?
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Yup, nice stock look., clean.
Thanks, I'm going to keep the stock wheels but I want to put custom wheels on it so bad.
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Not sure what the status is, but have you tried holding the gas pedal down? Got an update?
Sent from my VS990 using Tapatalk
Update
I first had the carb rebuilt and that wasn't it. When I took the fuel lines off the fuel pump I noticed that no fuel was running out of the gas line from the tank so I blew air into the fuel line and fuel started flowing out. After I got the new fuel pump on the motor just purrs and I'm so happy. Good thing I sell chips for a living.
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Beautiful truck
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Yes.
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Not sure what the status is, but have you tried holding the gas pedal down? Got an update?
Sent from my VS990 using Tapatalk
Update
I first had the carb rebuilt and that wasn't it. When I took the fuel lines off the fuel pump I noticed that no fuel was running out of the gas line from the tank so I blew air into the fuel line and fuel started flowing out. After I got the new fuel pump on the motor just purrs and I'm so happy. Good thing I sell chips for a living.
Awesome! Good to hear.
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Sounds like the pickup sock in the tank had some junk on it, might happen again.
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Thanks, now that it's getting a little cooler I have started taking the box off and then I will pull the tanks and rebuild them.
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Yup, nice stock look., clean.
Thanks, I'm going to keep the stock wheels but I want to put custom wheels on it so bad.
I know you do! But fight the temptation man! Nothing like a stock factory roll-out model. Going all stock is sometimes expensive and hard to do. But i think they look great as they came off the assembly line. In fact i dont think i have ever seen a mint cond. factory truck on this site ever. Maybe i'll start a new post?