Sam, I count three times I've advised you on the carb needing a new float, and on the fuel line mod.

If we make it four, will you go and try it before asking again what's wrong?

What about if we make it five?

An even half-dozen...?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Half a dozen, I am with Dan on this one.....

Carb kit and new float, and needle and seat, etc......

Either the float is sunk or not adjusted right.

In the meantime you should bend the float down slighly so there is more pressure on the needle and seat. Four bolts and the float bowl comes off so it is a quick fix until you get the carb kit.

I did this in a pinch once to stop the gurgling and bowling over......yeah it looks like witches brew going on......

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

My bad fellas...The 1bbl is the carb I know about the least, hence the 20-questions. Before I go replace everything I prefer to better understand 'why' things are happening. I figured the float was sinking or sunk and letting fuel past the needle, but given it has been 20 degrees here and I have had to put cardboard in front of the radiator to get better than warm out of the heater I didn't figure the carb was even close to hot enough to boil out the fuel after shutting it down. I guess both are happening.
Copy - replace float and rebuild carb. Won't go there again.

These carbs use a nonmetallic, nitrophyll float. Denver-metro was the first area in North America to experiment with oxygenated fuel (ethanol, MTBE, and/or TAME depending on the year and vendor) in 1987, and that's what's been offered at the pumps all winter long since that year. Current nitrophyll formulations are specifically designed to resist these what used to be considered contaminants in gasoline, but it's a pretty good bet your present float is original and has been steeping for long periods in fuel it wasn't designed to resist. Be sure to use the correct thick heat-insulating carb base gasket when you reinstall it.

Cardboard in front of the radiator suggests your thermostat isn't working correctly. Fetch a new 195° thermostat (I like the Stant SuperStat heavy duty model) and install it.

And make sure your manifold heat control valve is working.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan,

Will the ethanol eat the old rubber fuel lines? Cenex here in Black Daimond uses 10% ethanol.

It seems when I un-clamp the fuel lines to do some work they always leave my hand black, like they are melting. The lines are newly purchased.

Is there a better grade or silicone type that I should be asking for?

That is good too know about the new floats.

Thanks,

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Yep, I routinely go through and replace all the flexible fuel hoses in old cars with "Fuel Injection Hose", which is stamped "30R9" (the standard type is "30R7"). You have to use "fuel injection hose clamps" with this hose, and it's much more costly, but it's also much better hose (900 psi burst strength instead of 35 psi, much lower permeabilty, proof against whatever they can think of to add to the fuel.

Don't forget the short length between the fuel sender and the frame pipe.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan,

Is this stuff have the braid over it so I won't get called on the carpet at the tech inspections at track, Puget Sound Raceways?

I did your gas line mod and threw away the rusty metal gas line. Now I have a pretty short length coming up to the gas regulator, then fuel filter mounted on the fender then a long length over the valve cover to the carb. I believe it is the 30R7, I remember seeing that number.

The track kind of frowns on that much rubber even if your doing a test run.

If you PM me your email I could send a picture. There is quite a bit of line exposed so I need a number for the braided version.

Good point on the short piece from the chassis line to the fuel pump. Should I be putting a filter down there too? Before the fuel pump?

Thanks!

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

There might be 30R9 hose available with a braided covering (or perhaps a braided sleeve is available) -- I don't know. 30R9 hose per se is not braid-covered. Don't put a filter before the pump, that's a great way to cause vapour lock.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I've got the carb parts coming, including a float, and I have the old one out now. Is there any way to test the old float? It did not have any fuel in it, and it doesn't appear to have any significant flaws, and no air escaping when submerged in water. Not sure if those are any indications, but if it isn't a bad float then the carb is most likely boiling fuel out, correct? Maybe a leaking gasket? Again, I know what the problem is, and I know a rebuild with all the recommendations will most likely cure it, but what I'm most interested in is what's causing the problem, not necessarily how to fix it.

Again, the car gets around well enough and hasn't left me stranded, and I have most of the 2bbl parts ready to rebuild/install, so I'd really like to avoid dumping a lot of $ into perfecting a 1bbl system that I'm just going to remove anyway. See what I'm getting at?

The reason I asked about the fuel leaking out is because I wanted to see what kind of slant 6 issues...non-carb related that could cause the 2bbl system to have the same problem? The manifold heat valve and the fuel line mods are two great areas on concern and of course I'll be correcting those areas when I do the 2bbl swap.

Is there enough heat in the stock exhaust manifold to boil the fuel and make it gurgle out the carb...especially in 20* weather? Is there possible a cracked bowl gasket? Something else? I havent had a 1bbl apart ever, and I'm just asking questions.

I don't want to rebuild the carb and replace everything inside it just to have the same problems I'm having now. If the carb is junk, okay - I'll wait for the 2bbl. If the exhaust manifold is stuck, fine - I'll get at it with the 2bbl gig.

What else may cause the 2bbl system to lend the same problem I'm having with the 1bbl - that is my big question.

- Sam

Weigh it with a float scale. There are two different weights of Holley 1920 float: 7.5g and 12.5g. I don't recall which one has been discontinued; one of them has. You won't get sloshing fuel when you shake it, and you won't get air bubbles — that's for hollow metal or plastic floats; this is a cellular foam float.
Heavy float doesn't apply enough pressure to the needle and seat. Old needle and seat doesn't seal well. Metal pump-to-carb line heats up the fuel past the boiling point after you shut off the engine and there's no more cooling air blast from the radiator fan. Boiling fuel forces its way past the weak needle and seat weakly closed by the heavy float...overflows the float chamber and into the manifold it pours. Winter oxygenated gasoline has a lower boiling point than unadulterated gasoline, and everything boils at lower temperatures at 5,500 feet than at sea level.

Rebuild the carb, new float, electric choke, and fuel line mod — do them all.
If you get the 1bbl working well, you can sell it on here as a low-miles good-running original hand-rebuilt 1973 carburetor to help finance the 2bbl swap. It'll go, too. Good carburetors are always in demand. The only thing you might(!) hold off on is the electric choke swap, since you need a different kit for the 2bbl vs. 1bbl, but then again, you could sell the rebuilt 1bbl + electric choke as a package.
Yup, and it is very much worth your while to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan,

The Remflex.com gaskets are very good as well. They are very thick graphite and have alot of crush. I switched all three, the manifold, stove box and exhaust pipe joint with these. You torque them once, that's it!

Madmax,

Dan is right on doing the fuel line mod. That steel line boils the fuel and the needle and seat will leak. I had to run the float a little lower just to put enough pressure on the seat to shut it off. Now that I did the mod. it doesn't stink as much as it use to after shutting the car off. The carb still gets hot with the thick gasket under it but not as bad as before. Dan's fix is a good one!

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

Alrighty- gots a quick update .
Got all the super six 2bbl parts in place - Carter BBD carb that I rebuilt and looks to run very good, had to fab the kickdown and throttle linkage (couldn't find any locally). Did the fuel line mod, have the 3/8" base gasket, and all seemed to be pretty good to go, until I drove it into town for parts for another vehicle, and upon restarting it started having all kinds of 'running' issues .

It now has this issue: When cool, it'll start right up and purr like a kitten. WHen hot, driving around, it'll run great, pull hard, and purr like a kitten at idle, traffic stops, etc. But, shut it down, wait 10 minutes or so, restart, and will 'run', but very choppy...like it isn't getting enough fuel. It will run, but poorly - not well enough to drive. Pull off the air cleaner and yank the throttle - lots of accel pump - plenty of fuel.
Right then I pulled the top off the BBD...and it's full of fuel, but there are air bubbles coming through the needle and seat. The fuel line mod was done and the line isn't 'hot' per se nor is the filter, but it does touch the heater hose line coming over the top of the v-cover. It's definitely getting air in the system and making vapor...even with the fuel line mod'd. If I push down on the floats the air will fizz out the neddle and seat and not much fuel, but, the bowl is full of fuel. Plenty of accel pump shot...but real choppy running.

Let it cool down a while, it'll fire up and run great like nothing happened and drive around just happy as a clam.
It acts like a vacuum leak but after it cools off a bit it runs great so I figure I can rule out a vac leak, and there is no black smoke pouring out the pipe...so it's got to be a lack of fuel...but the bowl is full...?
It acts like vapor lock...but the bowl is full of fuel...not even hot fuel...and it runs great all the way across town...until I shut it off and it heat soaks...something?? When it's running choppy it is still 'running' so I know it's getting spark.
The tunings seem to be right on the mark and when it's running well it runs great - no accel stumble and much better power than before...but it acts like something inside the carb is temporarily preventing fuel from making it to the idle circuits and jets...but the bowl is full...?
Ignition issues or bad parts that'll intermittently run good and bad??
Either I'm missing something so simple or it's something else. Anyone?
I'll win this battle!
- Sam

If you're getting all kinds of air, it's probable you've got a leak on the intake side of the fuel pump, which sounds like it opens up only once it's hot. This kind of leak can be a complete bear to track down. Could be a fault with the pump itself (not a bad first suspect, given the low-low miles on this car), or the flex line between the frame hardline and the pump inlet, or the hardline itself, or the flex line between the frame hardline and the tank outlet.

I'd start by replacing the fuel pump and those two flex lines (w/30R9 hose and EFI clamps).

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan, can you please elaborate on this? I don't understand and I would like to know the reasoning.

Thanks!

A couple of thoughts on this:

Weighing floats is the right procedure, but if a molded float has had any time to dry out it is pointless. Also, I have never seen a molded float over 10 years old that was good, unless it just came out of a box.

Dan is right about looking for a leak between the tank and pump. I think it is best to follow the advice to just replace all the soft lines, it will likely fix the problem and there is no telling how old they are and when they will fail anyway. It takes less time than trying to find an air leak anyway.

An air leak in a steel line before the pump should weep fuel after running, but it may never actually drip.

If you use better hose like Dan is talking about it should be good for ten years or so. Not a bad idea, at least for under the car. I have been using 30r3 hose lately, it is between the 30r7 and 30r9. Not very expensive, uses normal clamps, 5/16" is rated at 300 psi and you can use it for trans cooler lines and power steering return lines if you get the right sizes too.