Got what I thought was a fresh rebulit Holley 4160 on my 79 351. It runs very rich and runs best with idle adjustment needle turned all the way in. When trying to back the needle off only 1 turn it stalls. I have played with the fuel valve adjusting nut without any differance. Anybody have thoughts as to what might be the problem??

 

I would say either the floats are too high( see if fuel is dripping out of the boosters down into the carb when idling), or you have a blown power valve.
If it backfired even once and it is an older carb, it blew the diaphram. You will need to pull the front bowl and metering block to replace it.
Jimmy

 

Ya I checked the floats and they seem ok, as for looking for gas at the boosters I'am really not sure what a booster is???? I pulled the front bowl and the power valve looks ok as it will hold a vaccum. I did have a couple of small backfires when I fired her up.Getting tired of fu$%king with this Holley maybe a new carb is the way to go. Do the new carbs get damaged with a small backfire?

 

No, the newer Holleys have power valve blow out protection. I would personally go with an Edelbrock if I was going to buy a new carb.

The boosters are the round inserts in each barrel where the fuel comes out at higher rpms. They are towards the top and are smaller diameter than the barrel itself.
Jimmy

 

workin hard

What size jets are on the primary side of the carb?
You may need to install smaller jets.

Does it run OK, just seems to be rich at idle and such. Like real rich smelling exhaust.

 

Ya it has a very rich smelling exhaust at idle and the plugs are filled with black carbon. I really don't know the jet size. I'am really leaning towards buying a new 80457s Holley from Summit @$260.00 I really do not want to spent the bucks but I have learned that my carb list # 6909 is really old and is an emissions carb. I have also learned that the small play in the throttle shaft my be causing vaccum problems. I looked at Edelbrock but none come out of the box with Ford auto trans kick-down .

 

workin hard

You can buy the auto trans kick down adapter for the Edelbrock Performer. Not very much. You can get them from Jegs, Summit, or probably locally.

On the Holley, it does sound like its probably over jetted.

 

If the carb was over jetted would it cause the idle adjusting needle to not responed to adjustment?? I can run it all the way in and it is there that it runs best. Running it out 2.5 times and it wants to bog down.

 

Well that does sound like a blown power valve. Which would also make it very rich. But you have checked it.

Hmmm?

 

So now what? Should I spend any more on this carb, buy a new one, or put the 2v autolite back on? I have been hearing that Holleys are hard to get running right,so I maybe a Edelbrock is the way to go. It just agravates me that they do not make a carb out of the box that has the Ford kick down . It's a option and with it puts the Edelbrock about $40 more that a Holley.

 

79, I assume 351M?

Would you feel comfortable with trying to go through the Holley again yourself?

I have had a little trouble with my 4160 getting pluged up in the front metering block. I took it off and blew compressed air through all the orfices in it and it was then fine. But it just idled bad.

 

It sounds like your air idle bleed holes in the top of the carb are plugged. Some have brass inserts and some don’t. Take a can of carb cleaner with the red straw on it and put it to the little holes in each end of the carb and make sure that they actually accept the fluid. There are 4 in each end of the carb. They are at the top of the venturies on a ledge by the vent tube. Wear some eye protection, as it will spray right back in your face if the straw in not on there tight or the hole is plugged. You may want to take out your air idle screws and shoot some fluid through those followed by some compressed air. This will clean up your idle circuit and have it purring in no time.

This causes most Holley complaints about idle quality. I consider this regular maintenance to keep a Holley razor sharp the way I like them. The better your air filter is the less often you will have to do it. If you run a K&N you should keep a can of WD or carb cleaner with you. They pass a lot of dust that will accumulate in the bleeds. Set your air idle screws with a vacuum gauge for the highest vacuum reading and then make them exactly equal. You should end up between ½ to 2 turns out. More than 3 and something is wrong.

 

Thanks for the tips guys but nothing seems to work. Please look at my new post "new carb holley vs edelbrock"