AAP Problem ? Or ?

[ARCHINSTL]

OK - don't 'diss me on this one because of my fragility...
It's cold, rainy, clammy, and muddy o/s in STL - and I don't have a garage (but I do have an old truck to drive in the meantime).

SYMPTOMS: Starts right up when cold - dies when accel pedal jabbed (you hear that "gasping/starving" sound), but not when slooowly depressed - when warm, sometimes dies when pedal jabbed - also when warm, takes 30+ seconds of turning starter to catch, and also will not start if accel pedal depressed at all (also if it dies when cold, takes a LOT longer for it to catch).

REMEDIES THUS FAR: New air filter (almost time to renew anyway), new fuel filter, new PCV (latter two items just made sense, although replaced about 3K miles ago - both looked OK, though).

POSSIBLE DIAGNOSIS: Faulty AAP - in reading here and elsewhere, this is common and seems to be indicative of my problem(s). Although - the carb is a reman FC (Edit: National Carburetors) unit 4K miles ago, with a lifetime warranty. The fuel pump was new last year. All vac lines were replaced last year as well. The distrib and associated wires, etc. are newish. I have not yet tested the AAP or anything else, as it is uncomfortable o/s (Hey-I've paid my dues working o/s!).

THANKS for any advice/similar experiences.
Tom M.

[jamiec]

yep sounds like the aap thats what mine
was doing when cold.some one had connected
the vac houses up to the tvsv wrong.

[takza]

Might check to see if the choke is setting OK? Vac leak?

[keith]

First thing I'd do is pull the air cleaner, look down the carburetor throat, hold choke open and then open the throttle and look for the squirt of gas from the accelerator pump.

[Petros]

sounds just like an accelerator pump not working. As noted just look down the throat of the carb and see if you see a squirt of fuel. The owners manual says to pump the pedal twice before strarting, this is to give it extra fuel on the cold engine. This can be fixed/replaced without removing the carb, you just remove the carb top and you expose it. Before you open the carb, make sure there is no squirt of fuel, and verify that the the pump linkage is connected and working properly (might just the linkage to the pump came loose).

Next I would look for a vac leak. Use a can of carb cleaner on all of the hoses and gaskets with it runing. If the speed changes when you spray a certain spot you found where the leak is located.

Good luck.

[ARCHINSTL]

When pumping the throttle linkage and looking into the carb throat when cold (and engine off), I do not see a "squirt" of fuel. I see what looks like a "mist" of smoky fuel.
When performing the same when the engine is running, I do not see a "squirt," but a kind of "splashing" of the fuel into the carb around the throttle (not choke) flap.
None of this is from the AAP port. The AAP appears OK, as it holds a vacuum when applied with the hand pump. There is/was no gas in the line to the TVSV. Any other check for this?
EDIT:
I forgot to include re the AAP: I did not see any real "squirt"of fuel from the tiny port in the top of the carb which I think is the one for the AAP - just a tiny, almost unnoticeable "pfft;" dunno if this is the right amount.
Thanks to all thus far.
Tom M.

[takza]

I'm beginning to think that my noisy fuel pump has a faulty check valve in it...allowing gas to drain back to the tank. Pumps OK...or so I think.

I'm pretty sure I've seen the accel pump putting gas into the carb...engine off...at least after it has run. It only needs to find fuel in the bowl?

[Petros]

I would say it sound like you need a new accerator pump. My first Turc acted just like this, instead of a clean squirt of fuel, I got a "puff" with a few drips. [did you look down inside using a flash light? it helps].

Once I replaced the pump, cleaned out the inside of the carb, cleaned ports, jets and bowl, I also replaced the needle valve on the float while I was at it, it solvded the problem. I never even removed the carb from the engine, I just removed the top cover (be careful, there are a lot of small parts).

Now it starts every time with just two pumps of the pedal, no stumbles or flat spots on acceleration.

The check valve in the fuel pump would not make a car with a carb hard to start because it starts off the fuel in the float bowl. Though if this isreally occuring the pump will soon fail since the if the check valve totally fails, then it can deleiver fuel to the carb.

[Typrus]

One pump and she'll start on nice mornings. 2-3 and she'll go on the cold. Coldest of cold and I have to help her get over it for the first 20 secs or so. Little gas to get it going, then gently rev to 2k, hold it for a sec, then she'll go from there.
I always try to let her warm up before I drive. Better in so many ways.

Thats what I get for having a pro rebuild my carb. Thank you Charley! See, the People's Republic of Boulder isn't all bad! lol

[ARCHINSTL]

Well, since the carb has a "lifetime warranty" from National Carburetors, I will be calling them tomorrow - couldn't get out and work today - too many storm and tornado warnings.

In the event I wind up having to do the work myself, I presume the basic carb kit from various vendors will suffice?
Thanks to all.
Tom M.

[takza]

Thats what I get for having a pro rebuild my carb. Thank you Charley! See, the People's Republic of Boulder isn't all bad! lol

I see the Chinese have taken over Boulder like they have Tibet....for shame for shame

[takza]

In the event I wind up having to do the work myself, I presume the basic carb kit from various vendors will suffice? Thanks to all. Tom M.

I found a kit at NAPA.

[ARCHINSTL]

Well - the AAP is holding a vacuum, and no gas can I smell in the tube: However, the accelerator pump plunger is very reluctant to move; it moved quite freely the last time I checked, which was several months ago. So as the throttle is pushed, the long spring on the linkage rod compresses, but is not strong enough to move the lever smartly.

The National tech thought the plunger cup had swollen, causing the stiffness, so back it went, although to Jacksonville, FL this time. He promised a 2-day turnaround, which seemed good. The fellow I spoke with is the one who actually rebuilds the Aisan carbs; his name is "Dave," if anyone has questions about a reman carb. He will check everything else on it. This particular carb actually was rebuilt at FC Products, which was a sister company, located in Chicago; it is now closed. I had the "feeling" from talking to him that the FC carbs may have had some issues...
Tom M.

[ARCHINSTL]

Well-
I am awaiting the Return Of The Carb...National misplaced it.
However, the tech wrote that what he did was:
1. Removed trash (his word) from the pump nozzle;
2. Replaced the accelerator pump;
3. Replaced the enrichment diaphragm (AAP diaphragm, I guess?).

Point 1 puzzles me, as before all of this happened, I had just renewed the fuel filter (I've used 4 since I got it 2 years ago, being anal about fuel filters), and once again, there was NO evidence of any crud, rust, etc., in the filters.
Tom M.

[keith]

Point 1 puzzles me, as before all of this happened, I had just renewed the fuel filter

Funny story here. When I was a lad (ok 20 something), we were going on a camping trip in the new (to him) camper he bought. The truck was a 64 Chevy. I don't remember why, but he wanted a new fuel filter in it so I put one in. It was late evening and very windy. While I was replacing the filter, this is a bronze filter that fits into the fuel inlet of the carburetor, a friend of his, who was chewing tobacco at the time, was talking to him.

The next morning we took off for Wyoming. The truck seemed to have a lot of low end torque, but had no high rpm and did not want to run over 60 mph. It had not been like that before. After two days of this, I pulled out the filter and guess what I found, a plug of tobacco. Apparently his friend ejected a wad, the wind caught it and it landed in the fuel filter that I had just put in. I must have been distracted between the time I put in the element and hooked up the fuel line, and it was semi dark at the time.