Holley carb 600cfm question.

[AZNUKLHD]

Hello all,

I have a holley 4 barrel 1850-5 1381 which I don't know what the 1381 means.

So it appears to be a 4160 model 600cfm. I purchased this truck a few months back which it had been setting in the desert for 7 years. So when it drops below 115 degrees I get some time to work on it.

Other than some loose vac lines, stuck float and faulty fuel pump I have been able to get it running/stopping/driving. However the truck doesnt want to idle. I used to have to prime it but have since been able to start using the pedal. Once started I can press the pedal to raise the rpm and half the time after a few minutes I can let off and it will run. I adjusted the curb idle which helped on that particular day. But the next day it was like starting from scratch.

After replacing the fuel pump I pulled the supply fuel line at the carb and had good fuel delivery. So it's either a carb tuning issue or a mechanical issue.

So my quesiton is at this point should I rebuild the carb? Or could it be a tuning issue?

My understanding these carbs are pretty easy to rebuild but also pretty affordable to replace as well.

Any input would be greatly appreciated.

Its a 1971 350 c.i with manual trans. I have no idea if the motor is original and/or if there were any other modifications done.

Thanks.....

[AZNUKLHD]

Forgot to mention outside of the idle issue it stalls when I press the go pedal. Meaning if I get it to idle I will try and drive it and when I press on the gas it gasps for air and almost dies. If I'm quick enough to hit the pedal I can get it to keep running. This consistently happens whether warm or cold.

[BugzC10]

Sitting that long..rebuild the carb. Check out the Holley web site for some good tips on adjusting the 4160. I have the same one...truck runs great.
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[geezer#99]

Check your timing first. Set it at 12 degrees. THen if that don't help rebuild the carb.

[WIDESIDE72]

Originally Posted by geezer#99

Check your timing first. Set it at 12 degrees. THen if that don't help rebuild the carb.

X2
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[Fitz]

Originally Posted by AZNUKLHD

Hello all,

I have a holley 4 barrel 1850-5 1381 which I don't know what the 1381 means.

So it appears to be a 4160 model 600cfm. I purchased this truck a few months back which it had been setting in the desert for 7 years. So when it drops below 115 degrees I get some time to work on it.

Other than some loose vac lines, stuck float and faulty fuel pump I have been able to get it running/stopping/driving. However the truck doesnt want to idle. I used to have to prime it but have since been able to start using the pedal. Once started I can press the pedal to raise the rpm and half the time after a few minutes I can let off and it will run. I adjusted the curb idle which helped on that particular day. But the next day it was like starting from scratch.

After replacing the fuel pump I pulled the supply fuel line at the carb and had good fuel delivery. So it's either a carb tuning issue or a mechanical issue.

So my quesiton is at this point should I rebuild the carb? Or could it be a tuning issue?

My understanding these carbs are pretty easy to rebuild but also pretty affordable to replace as well.

Any input would be greatly appreciated.

Its a 1971 350 c.i with manual trans. I have no idea if the motor is original and/or if there were any other modifications done.

Thanks.....

After sitting out in the heat for 7 years there wont be anything in the float bowl but dust, spiders and all of the bad stuff that plugs up the idle circuit in a Holley. Rebuild it then try to get the idle mixture set correctly using a vacuum gauge. Then you can try to get the stumble worked out but you won't be able to get initial timing set accurately until the engine has a stable idle. Here in Tucson. I have to Re-jet my 4150 double pumper for winter and summer due to density-altitude changes and Chandler isn't that different so, plan on buying new jets..

[Toxic Orange]

Any idea where the float level is on the carb? I see that it was stuck in your post, but is is set correctly now? if you have good delivery and a good float level then I would agree that the idle and transition circuit are not functioning correctly.

[AZNUKLHD]

I don't know what the float level is.

Thanks everyone... Looks like a rebuild is step one. Just wanted to make sure I am starting off on the right foot and making sure the holley is worth staying with.

I hope to get to it within the next week.

[Fitz]

Originally Posted by AZNUKLHD

I don't know what the float level is.

Thanks everyone... Looks like a rebuild is step one. Just wanted to make sure I am starting off on the right foot and making sure the holley is worth staying with.

I hope to get to it within the next week.

If you haven't removed the carb yet, start the engine and get it warm. Shut it off and remove the float sight screw. There should be just a very small dribble of gas out of that port when you gently bump the side of the truck when the float level is correctly set. If it runs out, the float is too high. If nothing comes out it is too low. in either case, using a large screwdriver and I think a 5/8 wrench loosen the nut and turn the screw clockwise to lower the float or counterclockwise to raise it. Start the motor and repeat the process until the float is in the correct position. This is important on a holley because you will never get the carb to work properly if the float isn't right. Hope this helps!