59 348 Won't Idle

[airsurf]

Hello all,
I have a 59 348 250hp with Carter 4bb and powerglide. It hasn't run in at least 5 years. Before that it hadn't run in a very long time so at that time we had the carb rebuilt, put a new gas tank in with all new fuel lines and clean gas. We got it running fairly good. After about another year of not running we tried and it wouldn't idle so my brother and I took the carb apart and there was some fine crud in the bowl. We cleaned it and got it running again. So I'm trying to get it going again. It's got new aviation gas in it. I primed it and it started pretty fast. But then after a short fast idle it starts to drift down and stall. Then when I try to start it again I have to hold the pedal near the floor and it will start firing, kind of like it's flooded but then it won't even try to idle. The accelerator pump shoots gas in when I move the throttle fast but not when I slowly move it. The choke is open and the engine is up to temp. I tried adjusting the two idle screws. I tried 1 1/2 turns each, then 2, then 1 turn each but seems to have no effect. I'm not a carb expert but I'm wondering what the t shaped yellowish piece is on the left side of this picture. It looks like it should be lifted by the throttle moving open but it is fully extended up. I can push it down but it springs right back up. I haven't messed with any vacuum lines or timing. Thanks for any advice
before I take the carb back to the shop.

 

[Don Jacks]

That lever is part of the power valve assembly.At an idle it should go down.Remove it and make certain that it is free of any deposits or varnish.There also may be a spring under there.This won't fix your idle problem however.I suspect an air leak in the base gasket or the gasket between the bowl and the base area of that carb.

 

[airsurf]

That lever moves freely but is spring loaded up. So at idle the lever is pulled down by vacuum within the carb?

 

[Don Jacks]

Yes,it's supposed to be pulled down against the spring at idle.As the throttle is opened and the vacuum drops,the spring moves the metering rods up enrichening the mixture at part throttle.

 

[heddrik]

You Da man Mr. Don! I didn t know this either.

 

[airsurf]

Gives you a good feeling when the first thing the carb guy says is ahh, a WCFB Carter.

 

[airsurf]

Got it back yesterday and looks great. He said had some crud in it and had a baggy with what he said was rust. He said it came out of the strainer and some in the bowl. I put a new tank in the car with new fuel lines 6 years ago. When I first ran it with the old tank I put a big filter in the fuel line right off the tank to catch any crap. My question, I think the tank I bought and installed was galvanized. The car has been in my dry Cali garage since then. It probably had about less than 5 gallons of gas which I recently replaced with aviation fuel. It looks pristine on the outside. Is there any chance the inside is rusting? I bought another filter to put in the fuel line before I fire it up just in case. I might have to get an endoscope borescope camera and look myself.

 

[Don Jacks]

I'd doubt that the tank is hurt badly,but check it.This was likely caused by ethonal in the fuel breaking down.You won't have that issue with AV gas,but these cars need to be run,not sit up.

 

[W Head]

Be sure and check your fuel filter. some filters is not for AV gas. I have a Wix screw on fuel filter just below the gas tank. Direction on the Wix box says " NOT FOR AV GAS". Don't know why, maybe Cecil knows.

W Head

59 Impala 409-2,4s

 

[DonSSDD]

If you have 6 year old ethanol in your gas tank, it may be rusting.

 

[oldskydog]

Be sure and check your fuel filter. some filters is not for AV gas. I have a Wix screw on fuel filter just below the gas tank. Direction on the Wix box says " NOT FOR AV GAS". Don't know why, maybe Cecil knows.

W Head

59 Impala 409-2,4s

Probably because it's not a "certified" part. All parts for standard airworthiness aicraft must be FAA/PMA certified.
Additionally if it has a paper element the adhesive in the paper may be affected by AVGAS and the last thing you want is paper fiber clogging your screens and carb/injection system. I would never use a paper filter in the fuel system. Mother Nature likes to humor us by allowing us to defy the Laws Of Gravity for a limited time. The amount of time is determined by us…….by choice, as in landing or by stupidity as in running out of gas or breaking your aerospace vehicle in flight…. the results of which can be extremely violent.

 

[airsurf]

I was only going to use the filter for a limited time and wanted a clear one so I could see any contamination. Never thought about the ramifications of a paper filter.

 

[airsurf]

So installed carb and started right up. Runs real smooth. Only question I have and I haven't asked the shop yet but the choke didn't fully open when it warmed up so I adjusted the choke with the black deal on the side that can be loosened and turned. But if I adjust it so that the choke will open fully then when it's cold the choke won't close fully.

 

[Don Jacks]

Set the choke only on a cold engine.Where's the power to the choke coming from? The condition that you're describing sounds like a weak source.

 

[oldskydog]

Heat stove.

 

[Don Jacks]

He's running a Holley Street Avenger,they all have electric chokes.

 

[oldskydog]

I guess I was mistaken when I thought it was a WCFB since that is what was pictured.

 

[airsurf]

It's the original WCFB. I'll try adjusting it when cold. How long should it take to fully open? Thanks.

 

[La Hot Rods]

If it gets is's heat from the exhaust, you can take the heat line loose from the choke housing, then start the car, you should feel some vacuum one the line fitting on the choke housing fitting. If no vacuum then there is some blockage in the carburetor.
If you have vacuum there, then check that you can blow through the line that goes to the exhaust manifold, if not then there is blockage in the line where it goes through the manifold.

 

[airsurf]

It does get heat from the exhaust and the tube gets very hot pretty quickly so I think it's pulling in hot air. Although the line isn't tightly sealed at the exhaust manifold so maybe the air doesn't get quite hot enough. The choke did open but just not quite all the way. Just had the carb rebuilt. Not sure how the choke tube is supposed to attach to the manifold. The tube is larger diameter than the hole but I'm wondering if part of the tube is broken off in there. Doesn't look like it though. Also, in looking for a new one I see there is heat riser tube insulation available. Is that stock?