Carburetor 454 won’t turn on

[malc1080]

Hi I have a 1980 c10 454 with a Holley 4160 carb. The truck was running good for months but now it won’t start. I have to pump the gas pedal repeatedly while cranking so it can start up. It then dies. When it was running, I would floor it and it will hesitate to run and will do popping noise in the exhaust. It started when I switched to the 2nd gas tank that hasn’t been used in a long time. I have used up the tank and went through a couple fresh gas and was running for a while with that tank. I have used carb cleaner down the barrel while working the throttle and have replaced the fuel filter on the carb line. My question is how can I get it running ? Do I have to change the mechanical fuel pump, change the fuel lines, clean the gas tank , and do an carburetor rebuilt with the renew kit? Any help and advise will be much appreciated! Thank you and happy Mother’s Day!

[farmall]

You have a fuel pressure gauge. What does it show when cranking? Is there fuel in the filter when cranking? Symptoms are lean. Vacuum leak?

[malc1080]

That fuel pressure doesn’t work unfortunately. That’s how I got the truck . Yea there is fuel in the glass filter and I sprayed carb cleaner around the intake for leaks and there wasn’t any . So I’m not getting enough fuel right? Guess I will have to redo everything plus new spark plugs and cable?

[Dead Parrot]

Check the suction lines from the tanks to the valve and the valve to the frame. Those are out of sight and often forgotten about.

Try filling the carb bowls via the two vents and see if it starts normally. It won't run very long on just the bowls but it should tell you if your issue is fuel or other.

Double check the timing just in case the hold down bolt picked the time you swapped to the other tank to loosen and let the distributor change timing.

Possible enough rust and crud got through that filter and is now in the carb. If your testing keeps pointing at fuel, I would start with a carb refresh.

Might put a filter between the frame and fuel pump to keep tank crud from reaching the pump.

[malc1080]

Thank you both for the replies! How do I check the suction lines ? And is that the lines attached to the tank?

Ok I’ll add fuel to the primary two throat vents? Where the jet squirt fuel right?


I’ll definitely check the timing once I can get my hands on a timing light !

I think rust was what caused all this. I’ll definitely put a second fuel filter between the frame and fuel pump

[malc1080]

The only problem is checking the timing is going to be tough if I can’t get the truck to stay running 😔

[Dead Parrot]

Suction lines are the ones from tanks to switch valve and from valve to frame and from frame to fuel pump. A hole in one of those lets air it and can limit or prevent fuel flow.

You should be able to add fuel into those two pipes with angled ends on the carb top. They should be the fuel bowl vents.

True on the timing and running engine! For a quick check, see if the distributor is still tight and won't move. If it is, probably safe to assume it hasn't moved until you can confirm with a timing check. My suggestion on the timing check is because poor timing can mimic some fuel issues and it is a lot easier to make sure the timing is good then dropping fuel tanks.

Based on the rust in that filter plus the problem starting when you started using the 2nd tank, I think your rust theory is probably correct.

Please make sure that clear filter is an automotive filter and not one of those outboard motor filters. The outboard filters are designed for the suction side only and are not pressure rated.

[blazer2007]

small crack in fuel line,?

[malc1080]

Thank you for the replies!
Ok once I get home I’ll go underneath and take some pictures so i can get some help on identifying the suction lines. I’ll check for anything usually.

I’ll try adding fuel through the pipes and see what happens.

I’ll also check for a loose distributor. I hope it’s not that since it was working perfectly before.

So if it’s the rust, I’ll go ahead and start on repairing all the things I mentioned, fuel lines, carburetor rebuilt, fuel pump , spark plus and wires . I just don’t know which fuel pump to get. I see they vary from GPH . From 40 bucks on LMC to over 100 On summit racing.
My 454 is cammed and that’s all I know about it.

Damn I got it at the auto store . I’ll go back and retrieve the package from the trash to make sure .

[malc1080]

I’ll check for any cracks!

[blazer2007]

When I had a small crack in the fuel line it would start better on a full tank of gas and as the tank emptied it would get harder to start. Check where the bends are. It didn,t leak that you could see drips but when I found it you could see it wet. I chased it and spent money on new fuel pump etc.

[malc1080]

I’ll check! Thanks for the advice. Need to get under there. Didn’t have time today to do it. Tomorrow for sure!

[Dead Parrot]

If you got the filter at an auto store, its probably OK. Just make sure it is rated for the pressure side of the system.

The ones I am thinking about look similar but are found in the marine sections of Walmart or Academy. They are meant to go between the 6 gallon boat gas tanks and the outboard where the outboard is sucking the gas out of the tank.

IMO:
1 Only use gas from the pre-trouble tank.
2 Add the filter between the frame and fuel pump. (low cost and easy)
3 Clean and refresh the carb.
Only if the above doesn't clear the problem would I worry about the fuel pump. They are normally fairly durable.
Once you get the truck running good - then worry about dropping the 2nd tank and inspecting things. Very possible the sock on the sender is toast and let years of crud into the system. Or added bits of sock to the problem. (When I replaced the leaking driver's side tank on my 75, the remains of the original sender sock was half sucked into the intake pipe. I do have a filter between the frame and fuel pump so no harm done.)

[malc1080]

Thank you so much for the help. And every too!
The filter was made by a brand called mr gasket and doesn’t say the psi . Just says not for fuel injection.
Ok I’ll only use the good and I’ll add a fuel filter under! Where is between the frame? Is it just side the bed frame?
And I’ll do the carb with holleys renew kit! That’s going to be tough but I’m always looking at YouTube videos! This is my first c10 and new to everything! Ready to learn and one day help others for free.

[malc1080]

Is the sender inside the gas tank?

[malc1080]

And will I need 2 filter between the frame one for each tank or one before the fuel pump for both tanks?

[truckin 79]

The best thing about a holley carb is checking to see of fuel is in bowls. On the passenger side you see those flat screws on bowls? Gently remove sight plugs and fuel should dribble out of it, then you know it is fine. If fuel comes pouring out then it is probably flooded. If it is flooded you can remove needle and seat from top of carb bowl and see what kind of debris might be in there. You can proably find a youtube video that shows you all this. That way you are not tearing apart things you dont have to. Also you can run to parts store and get a spark tester, looks like a spark plug that you ground on metal and you should see a spark jump across. Quick easy checks on fuel and spark.

[malc1080]

Originally Posted by truckin 79

The best thing about a holley carb is checking to see of fuel is in bowls. On the passenger side you see those flat screws on bowls? Gently remove sight plugs and fuel should dribble out of it, then you know it is fine. If fuel comes pouring out then it is probably flooded. If it is flooded you can remove needle and seat from top of carb bowl and see what kind of debris might be in there. You can proably find a youtube video that shows you all this. That way you are not tearing apart things you dont have to. Also you can run to parts store and get a spark tester, looks like a spark plug that you ground on metal and you should see a spark jump across. Quick easy checks on fuel and spark.

Ok I was came back from getting the truck to run by closing the manual choke and holding the gas to keep it running. I then turned it off and removed screws as this is what I found. The first fuel bowl just dribbled out and i can see the fuel . If I rocked the truck side to side it will dribble. Now the fuel bowl behind it had no fuel at all. And I have gas linking from the diaphragm and it is wet between the gasket on the adapter plate that’s the carburetor sits on top off. It’s on the driver side. I have provided pictures and I’m pointing at it with a screw driver ! Thanks !

[malc1080]

I have no idea by my pictures are being uploaded sideways

[truckin 79]

Okay I would check the float needle seats on both bowls. You see the large flat screw in middle of bowl on top. Loosen the flat screw and take it off. You can usually turn nut by hand to get needle seat out. Mark on one side of nut with permanent marker or scribe and count the number of turns it takes to unscrew needle seat. That gives you a good starting point when you put them back in. There is probably crap in between needle and seat. Also change out that glass filter those are junk and put on a real universal fram G15 or the like.

To really dial in fuel bowls once again fuel should just dribble out of bottom of side sight plug. Holley also makes clear sight plugs so that you dont get fuel all over and possibly start truck on fire. Good luck

[malc1080]

Originally Posted by truckin 79

Okay I would check the float needle seats on both bowls. You see the large flat screw in middle of bowl on top. Loosen the flat screw and take it off. You can usually turn nut by hand to get needle seat out. Mark on one side of nut with permanent marker or scribe and count the number of turns it takes to unscrew needle seat. That gives you a good starting point when you put them back in. There is probably crap in between needle and seat. Also change out that glass filter those are junk and put on a real universal fram G15 or the like.

To really dial in fuel bowls once again fuel should just dribble out of bottom of side sight plug. Holley also makes clear sight plugs so that you dont get fuel all over and possibly start truck on fire. Good luck

Thank you so much! I’ll be adding a filter under the truck before the pump, replace the screws for see through and just buy a Holley renew kit to replace he gaskets and clean out the needle and seat!

[Dead Parrot]

Not very knowledgeable on Holleys. Is there a filter in those housings where the gas line enters the carb? Even a simple screen filter might be full of rust that got past that old filter. Qjets put a filter in a similar looking housing and Eddy carbs have small internal screens.

[malc1080]

Originally Posted by Dead Parrot

Not very knowledgeable on Holleys. Is there a filter in those housings where the gas line enters the carb? Even a simple screen filter might be full of rust that got past that old filter. Qjets put a filter in a similar looking housing and Eddy carbs have small internal screens.

I think I’ll wait on my carburetor book I purchased. LMC sells those manuals so I got one used so I’ll wait for that and start taking it apart and post that here so anyone who ever has the same issue and just follow along! For the love of c10s!