If any of you are following this you know I've been having alot of trouble getting my used Holley Street Avenger to behave. I recently took off the primary float bowl because I couldn't get the float to adjust. The reason turned out to be that the needle/seat was screwed way down into the bowl out of reach of the adjustment nut which was also stripped on one side. I rebuilt it and flipped the nut over and I set the float initially as recommended in my Haynes manual so that there was a pencil's width between the top of the float and the roof of the bowl when turned upside down. That turned out to be way too high, the carb started spouting gas like a fountain.
I came across an article on Ford Muscle that dealth with rebuilding Holleys and it had this tidbit in it
"19. With the needles and seats in, re-attach the floats. Setting Holley float levels is somewhat tricky, especially with the engine running. We recommend setting it now. Adjust the screw so that the top of the float is level with the bottom of the sight hole. Note that we have replaced the stock hollow brass floats with Nitrophyl floats. This is not neccesary, but chances are if your carb is as old as ours, the brass has corroded and may have pin hole leaks, or the brazing has separated. Upgrading now is cheap insurance against a hard to find fuel level problem."
Obviously that's quite different than what the Haynes manual said. Just now after the carb's latest gas bath I drained the excess out of the site hole and tried to do what Ford Muscle said. I got the float to sit ALMOST level with the site hole before the needle/seat slipped down out of the nut again :mad: This doesn't seem all that natural. Experiences?
Oh also I have a 110 gph pump. As far as I know 130 gph is where you start to need a regulator.
GAA!!!!!! I tried it again and the car started again and ran a minute on fast idle but I had to shut it down because I saw gas working its way up through the gasket seal on the adjustment nut. I opened the site plug and was greeted by another rush of gasoline! The float adjustment is AS LOW AS IT CAN POSSIBLY GET and it's still doing this! The needle and seat assembly is down below the grip of the adjustment nut, it cannot be adjusted lower. The float is totally submerged, the pressure of that should be jamming the needle valve closed and cutting off the gas flow but it's not. I had that thing in my hand last week, it looked fine. And ironically it wasn't flooding over like this before I took apart the float bowl. It looked straightforward as hell! What could I have screwed up?
And so you know the pump isn't a new addition, it's been on the car almost a year and my Motorcraft 2150 never did anything like this.
Wait a minute....if the accelerator pump was out of adjustment and the lever propped down would it allow an additional stream of fuel into the bowl? I don't even quite know how that accel pump works, I'm just thinking out loud.
Sounds like you may have a damaged needle valve or seat... But you say it looks good. I haven't been inside any of the newer Holleys, so I don't know if there are any quirks to installing the valve or gaskets...
BTW you are using Holley type replacement parts, some of the in the Jiffy kits was junk...
Well the Street Avenger is based on the 4160. The float bowl looks just like the one in the book. The only quirk about installing the needle/seat was greasing the O-ring which I did. As yet I haven't actually replaced anything internal but if I decide to I'll make sure it's Holley parts.
Is the float... um... floating? If it's got a pinhole in it or if it isn't floating at the correct level it won't close the needle valve and will allow too much fuel in. Also, is the float pivot (where it's attached to the needle valve) bent at all? When you replaced the needle valve and seat, did you compare them to the ones you removed? If the valve is shorter it might have to move further to seat (if it can seat at all)
Years ago when attempting to cure an excessive fuel problem on an old friend's '77 F350 dually I had to tweak the float to get it to stop pumping fuel up through the vent hole. It was a fun problem to try to fix...
Also, not familiar with the Holley, but is it possible to run the engine with the float cover off? If so you could try pulling up on the float manually to see if it shuts the fuel flow off (IIRC that's how I discovered the problem on that old Motorcraft).
Well I haven't replaced the needle and seat but the fact that it's able to slip down out of the nut's grasp has made me wonder if it's even the right one. As for the float I made sure it wasn't bent and I didn't feel any fluid inside it but I didn't pay special attention to it. I'll take the bowl off again tomorrow and try to figure this out.
Okay I didn't feel like wondering about it all night so I just ran out and unscrewed the needle/seat from the bowl (nice to be able to do that) and sure enough there was a decent clod of something on the needle. It probably came loose from some crevice of the metering block. I'll give it another go tomorrow and see how it reacts.
if you are running the 110gph electric blue pump with no regulator you probly have 14 psi or more of fuel pressure.
It's a mechanical pump actually.
may not hurt to check the pressure the relief valve maybe stuck closed
Possible. But since the pump is fairly new and this didn't start until the carb swap, I'll leave the pressure check for later. The dirt I found on the needle and seat could easily be the problem and I'll find out soon.
Dirt is a bad thing for a holley may not hurt to put a good filter between the f/p and carb.
Yay! I got the floats adjusted right. No more flooding or fuel starving. But something is still off, the vacuum reading at idle keeps jumping around mostly between 17-19 inches (sea level). That's well within the green "good motor" range of the gauge but I know it's not supposed to search back and forth like that. I tried tuning the mixture to no positive effect. It's on my mind that if there was gunk on the needle/seat then it's entirely possible it's in the jets or even the metering block itself. Sound logical? I'll probably take it apart later and see.
could be a vaccume leak or the air adjustment not set correctly.
Does the car have a aftermarket cam?
It has a non roller HO cam. Nothing too aggressive. I've started wondering if the plugs became gas fouled when the carb kept flooding over. I'm also going to make sure there's clearance between the throttle arm and the accelerator pump arm in case it's leaking small amounts of fuel into the engine at idle. I guess I can look again for vacuum leaks, we'll see.
Well I just checked the accel pump and it was being pressed down on with a fair bit of tension. I adjusted it to spec and we'll see in the morning. Out of curiousity what would you guys consider a normal mixture screw setting for a Holley on a Mustang-esque 302? Ford Muscle says if you have to go more than 2 then you have some kind of problem elsewhere.
Pretty much the same thing found in most repair manuals:
http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm (http://"http://www.classictruckshop.com/clubs/earlyburbs/projects/vac/uum.htm")
Okay I started the car again and didn't change any settings, I just observed for a bit. And one thing in particular caught my interest. The cheap plastic fuel filter in the line just in front of the distributor was nearly full of gas at first and the car ran smooth enough but after a while the level of gas in the filter dropped lower and lower until it was almost empty (see picture). The car maintained its RPM but was getting moderately rough. I don't know if that's remotely normal behaviour for a fuel filter but if it isn't it seems I have a problem. I know your first thought would be bad pump but that's a Holley pump, less than a year old and it never gave me any trouble until the carb swap (although I didn't used to have a see-through filter). Any other ideas about this? Could the fuel be vaporizing in the line? I don't know....
Starting to lean towards this being vapor lock....Incidently I never used an inline filter before because the stock carburetor used a small brass one that screwed into the bowl. I know my Holley has filters in the bowl that are meant to be secondary only and they warn that I should use an inline filter as well. I finally looked up a picture of one of those filters and presumably this is one in the picture below. Certainly looks as competent as any filter I would have had. Has anyone relied solely on them? Cause I think this oversized junk filter I'm using is providing a place for vapor to build and hold back fuel flow.
Okay I just came back from a parts store and one guy brought up the possibility that I need a spacer plate to further insulate the Holley because it may be overheating and forcing vapor down the line. Right now all that stands between the carb and the manifold is a felt gasket so I guess it's possible. I didn't do any more because clearance is limited, maybe I can fit something small though.
Just ordered a .25 inch heat disappator plate. Wish me luck.
should help some, the filters they do ok but ive seen dirt get past them
i like to use the clear fuel filters like the fram G6 .