firechicken_3

iTrader: (4)

Hey guys does anyone know if the center hung bowls use a different needle and seat than the side hung bowls?

Im having an issue where i cannot get my secondary float low enough to not overflow the sight plug.... im close but i am OUT of adjustment to lower the float if i try to go farther the nut will no longer engage the needle assembly.

My carb is a center hung, with the plastic float which appears to be in good shape and not saturated. Based on bowl shape i suspect the sidehungs could be a shorter version and wonder if i may have the wrong ones.


After being at operating temp the engine acts flooded on restart. I have observed the secondary blades are wet and a puddle of fuel IN not on the intake.

InfernalVortex

iTrader: (4)

Sounds like you have the same problem I, along with several others have....

But you cant get the fuel to sit right below the sight plug?

Either way, in my case after the car sits a while the hot intake and hot carb evaporate off fuel that gets vented out the bowl vents, but the fuel sitting in the feed lines that gets just as hot has nowhere to go. As soon as the fuel line i repressurized the fuel vapor by the needle/seat assembly blows straight through and the turbulence makes a mess and pushes some fuel straight out the bowl vents and air bleeds and straight into the engine.

If you have someone watch it you can watch a small geyser of fuel blow out the bowl vent if that's the case.

But a high float level will definitely exacerbate that, and I still find it weird you say you cant seem to get the float level low enough. Is that low enough according to the sight plug, or are you trying to go lower to prevent your fuel spewing issue? Because if the latter, it will help, but it wont cure it.

firechicken_3

iTrader: (4)

i couldnt get it low enough by sight plug..... but yeah i started in on this in an effort to lower it to attempt to help the issue.

I called holley this morning and learned that even though they have different part numbers for the center and side hung bowl the needle and seats are apparently the same although i am tempted to order one of each just for kicks.. The tech suggested that i just bent the tab on the float arm to get me back within an adjustable range. I did so and was able to lower the fuel level below the sight hole.

I found some of your posts on the issue infernal, its certainly a similar problem.

My car uses a standard mechanical pump with factory fuel lines routed where they belong. I have removed my charcoal can, but the vapor line is run through a filter to prevent creepy crawlers from climbing in and extended below the car so my tank doesnt build pressure.

The odd thing is that 2 springs ago i after this carb had been on the car with no issues since the previous late summer, I swapped on an electric choke, and quickchange secondary spring housing and then began to notice this issue... I have since put the manual choke back on as I couldnt get the electric to work correctly. And the issue persists. Somewhere in there i went to longtube headers custom y pipe.... but I cannot recall when exactly so that may be related in some way.

Its frustrating for sure, but probably not a massive problem to live with mostly an annoyance. I have never watched as someone began cranking the car while hot to observe the geyser of fuel you describe though....I'll try it here shortly the car has been sitting about 30 mins now.

firechicken_3

iTrader: (4)

No fuel shooting from the vent tubes now at least, i suppose it could have been before i lowered the float level.

Another thought i had while staring at the engine. I dont have a filter past the pump anymore.... prior to trying the electric choke i had a summit dual feed line on it with a filter in it.... when i had my old carb i had a glass body filter .....

Never in the 8 years with that carb had this problem nor does my dads nova or a buddys v8 s-10, which both have filters after the mechanical pump. could the filter be acting as an expansion chamber/buffer and preventing the hot fuel from rushing ahead so quickly?

When i put the electic choke on it i had to get a different fuel line as the summit one didnt clear the choke housing because i had shortened the legs of it to allow clearance for the filter section to run past a fitting on my intake

InfernalVortex

iTrader: (4)

Im having a little trouble understanding exactly how you had it set up but it sounds plausible, but all the fuel thats gone from liquid to gas would, by nature, gravitate upwards as high as it could in the lines. I suppose whatever is below the filter would get somewhat stuck in the filter assembly.

However, all I can say is after the car sits for an hour, I can put my hand on the carb or the feed lines (either over the front of the engine or right next to the carb) and they are VERY hot to the touch. They will burn you if you leave your hand on them for moer than a couple of moments. After I run it for a minute and there's new fuel in the feed lines, the feed lines are cool to the touch again. The carb itself is still hot, but notably cooler than it was. That narrows down my issue to just carburetor heat soak. No way around that through fuel line routing. A phenolic spacer would theoretically fix it but I never saw any case online of that actually working.

I actually came across one guy who installed some nitrous purge solenoids in his carb, and he had it setup to feed fuel back to the tank. Clever solution, he said it worked...

I personally have just started cycling the fuel pump on and off on hot days on hot restarts. Not ideal, but whatever. It just perplexes me how common this problem is, and yet how many people dont have it. It seems to strike random cars. Havent really figured out the common thread yet.

This is how my feed line is routed in case you find some kind of relevance.