idle adjustment
Senior User
Joined: Aug 2000
Posts: 407
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idle adjustment
I have the Holley four barrel carb on my `85 460. The block off plugs have been removed from the idle mixture adjusters but I can not tell what type of tool is needed to turn the screws. Does anyone know the specific tool needed to make this adjustment?
Thanks to all,
Mark
Thanks to all,
Mark
Senior User
Joined: Aug 2000
Posts: 407
Likes: 0
idle adjustment
Really, there are four? I have never seen idle adjustment screws on the secondary side when they are vacuum operated. I will have to check it out. BTW, do you know what model, under the Holley numbering system, these carbs fall under? It seems a lot like a 4160 but there are certainly some differences.
Thanks,
Mark
Thanks,
Mark
Senior User
Joined: Aug 2000
Posts: 407
Likes: 0
idle adjustment
Beetle,
Well, you are absolutely correct. There are four mixture screws on my carb. Thanks for the good info. I tried a bunch of small allen wrenches and could not get any to fit. It is tough trying to see up under the fuel bowl while trying to see how close in size a wrench is. I tried all my metric wrenches now I need to dig out all my SAE ones.
I had pretty much narrowed it down to a model 4180. On Holley’s carb listing they have about a dozen different model 4180’s shown. None of the carb numbers listed matches any of the numbers on mine. Holley’s numbers are 0-80xxx while the closest I have to that is 50259 which, on the tag, has the word “List” before this number. So how do I determine which 4180 I have.
This goes to the bigger issue of probably needing to replace this carb. If I do (and if I go with another Holley) I will probably use the 1850. But, since this carb is used on a motor that does a lot of hauling and towing I want to make sure I use a power valve in any new carb that will match the demands on the engine. It seems as though 4180’s (at least some) use two stage power valves.
Anything else you can share with me would be greatly appreciated.
Thanks,
Mark
Well, you are absolutely correct. There are four mixture screws on my carb. Thanks for the good info. I tried a bunch of small allen wrenches and could not get any to fit. It is tough trying to see up under the fuel bowl while trying to see how close in size a wrench is. I tried all my metric wrenches now I need to dig out all my SAE ones.
I had pretty much narrowed it down to a model 4180. On Holley’s carb listing they have about a dozen different model 4180’s shown. None of the carb numbers listed matches any of the numbers on mine. Holley’s numbers are 0-80xxx while the closest I have to that is 50259 which, on the tag, has the word “List” before this number. So how do I determine which 4180 I have.
This goes to the bigger issue of probably needing to replace this carb. If I do (and if I go with another Holley) I will probably use the 1850. But, since this carb is used on a motor that does a lot of hauling and towing I want to make sure I use a power valve in any new carb that will match the demands on the engine. It seems as though 4180’s (at least some) use two stage power valves.
Anything else you can share with me would be greatly appreciated.
Thanks,
Mark
Senior User
Joined: Nov 2000
Posts: 285
Likes: 1
From: sunny san diego
idle adjustment
If your carb has never been opened up, it probably has a 2 stage power valve. You should replace it with a holly 6.5 powervalve. This will give you a very slight increase in milage when cruising and extra fuel when under a load, decreasing a tendency to ping. Stick with the holly, once setup properly it works excellent.
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New User
Joined: Mar 2005
Posts: 14
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From: puyallup wash
Idle mixture screws on holly 4180
idle mixture screws are 3/32 on my 1984 ford 460. Getting at them is impossible. I took the carb off, took it to my local hardware that handles an assortment of small allen wrenches. Bought several for .39 cents each. Inserted the allenwrenches into the idle mixture screw and used large blue rubber bands to to keep them from falling out while I renistalled the carb. I also found a tool at the local auto parts store. It is a long flexable snake with a small barrel and allen wrench that fits into the idle mixture part. This is still a lot of trouble. With all the wiring and plumbing on the 460 ford it is a real problem but can be done. Good luck. I would suggest finding a good local carb guy and let him earn a couple bucks. You'll be happy and he can feed the kids.
Ray.
Ray.
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Post Fiend
Joined: Mar 2004
Posts: 6,056
Likes: 8
From: Union, Washington
Go buy a carb adjusting tool. Mine (I've had it so long I have no idea where I got it) has the two different adjusters for the on each end of a spring that lets you bend the tool to reach those hard to reach mixture screws. Craftsman use to have them and Snap on also. I would suspect most good auto parts store will have something like it.