'74 Scamp, 225 rebuild .060 off the head, ported and polished head, new valve job, 264 Isky cam, Holley/Weber 5200/ 32/36 progressive carb. Rebuilt 904 and new Hughes converter. 700 miles on the rebuild. Finally got it tuned pretty good. Valves adjusted .018 as recommended by Isky. 10 deg BTDC. Stock 2 barrel manifold intake and exhaust. Brand new 2 1/4 exhaust system all the way out. Purrs like a kitten until you come to a light and it bogs and dies. The only way to keep it from dying is to shift manually into neutral and then shift to drive.

Vacuum leak, carb adjust, jets? Where do I start?

Thanks

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Sweet Emotion

I had the same problem on my super six,part of the problem was a vac leak,I used 3 throttle bodies from scrap carter bbd,sandwicthed them together to make a spacer under the carb for better throttle response,I got the vac leak figured out,it would still die at a stop,when I would get off the gas it would now drop to an idle for a second then die out,it ended up being metering rods and air and fuel mix,the metering rod were dropping into the carb to far making it to lean,some fiddling around and now it runs great ,except for fuel mileage thats on the rough side,wow thats a hell ofa run on sentence,o well good luck,,,,speedfreak.

Might have to adjust your distributor advance curve. As the rpm drops at idle, it may be pulling timing out. As the timing comes out, the rpm drops further, and then more timing comes out, etc.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

It's possible I may have gotten the emulsion tubes mixed up when I put the carb bck together. I wonder if that could do it? Also my jets for this carb are 65 on the primary idle and 70 on the secondary idle jet, 180 on both main jets and 195 on the air correctors. I was getting a dieseling efftect with 57/65 145/160 195/195. So I yanked the carb and pulled it apart and blew it out. Also when I rebuilt the carb with a brand new rebuild kit a couple weeks ago, I don't recall seeing any rubber washers for the idle jets but a blown up picture I have shows them. It doesn't seem like it's leaking around them but they may not be seating properly. Not sure.

As far as distributer goes. I did put a new vac advance on it because the old one was shot. The distributer is an electronic type, no points. I did adjust the gap a while back. .008 I think. I also remove the gear and replaced it. I completely cleaned it up and put a little 3 in 1 oil on the springs. I haven't done anything to the adjustment of the tensioner adjuster inside so I could do that.

Is there a test I could do on the distributer while it's on the car to see if that's the problem?

Also how much should the idle drop going from park to drive? It seems to be dropping from about 900 to around 700 or maybe lower.

Thanks for the help.

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Sweet Emotion

Do you have power brakes?

No, manual brakes.

I looked in the Holley rebuild kit instructions and apparently there is no idle jet gasket on the Holley 5200. One other thing is I don't have the air breather connected to the carb right now and I have the hole plugged on the valve cover and the air cleaner. Also I've got the little square Weber style air cleaner which means it's breathing air from right above the manifolds which may not be the best air for it. I put that cleaner on it to get things tuned up since i'm still dorking with jets and such. Not sure the air cleaner would really cause my problem.

Are you supposed to set idle while it's in drive? What should the idle be with it in drive?

Thanks

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Sweet Emotion

The idle speed and mixture are properly set with the trans in Park or Neutral, high beam headlamps ON, and A/C (if so equipped) ON.

Your drop from 900 to 700 when going from Park to Drive is fairly normal.

Does this behavior occur when cold OR hot, or only when hot? If the latter, it is quite likely a heat-induced problem. How long does it take after you come to a stop for the engine to stall? Does it stall immediately, or does it gradually roughen, bog, THEN stall?

What is the status of your heat riser valve (present, absent, stuck, working)?

How is your fuel line routed between the fuel pump and the carb, and what is it made of (metal, rubber)?

Happens only when hot but I think the choke may be masking it when cold.

The line is rubber from the fuel pum to the carb. It runs up to the alternator braket and I have a filter and pressure regulator tie to the bracket. Then from th regulator I jump over to the AC unit with a high arch and then it curls around to a pressure gauge and into a 6 inck long brass pipe to the carb. No filter at or near the car.

The heat riser is functioning as the round counter wieght moves freely when accelration occurs.

I bought some rubber o rings and installed them in the idle jet holders. Even though the Holley picture doesn't show them it couldn't hurt as long as I can tighten them properly without squishing out the oring and it worked fine. Also I hooked up the breather and I did find one line than goes to the EGR disconnect and I plugged it. I also changed the idle jets back to 57/60 because I wasn't getting any response from the A/F mixture screw and now I do.

I broke the cardinal rule by changing many things at once but it may have cured the problem. Likely the EGR vacuum hose but hard to tel. I get a smooth idle at about 800 and it drops to about 600 or so when in park.

For what its worth the AC is not connected presently. Also I need to get the stock air cleaner back on as soon as I am comfortable with the way it runs.

I'll drive it tonight about 45 miles and report back later tonight. Keep your fingers crossed. Thanks for all the help.

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Sweet Emotion

Correction, drops to 600 when in drive.

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Sweet Emotion

I would try to fiddle with valvle lash, trying to find any value that might eliminate this bog. In my experience, my cam grinder told me to set the lash to .08 .08, now I'm .10 .15 and the idle smoothed out pretty nice. I had hesitation on idle. Another thing to try out might be advancing the timing another 2º BTDC...

Well I spoke too soon as the problem is still there. I plugged every vacuum line including the vac advance and it is still there. Then I plugged the PCV inlet to the carb base and I think I found the problem. I can't remember where I got the PCV valve but I suspect it may not be the right one. I'll get a replacement today. Also I am wondering about the correct placement of the PCV inlet. I have the Proline Fuel Carb adapter for the Weber/Holley 2 barrel. It has the tapped hole in the secondary side of the carb. Is this correct? Also I bought a book on Weber carburetors and noticed they show a placement guide for all types of manifolds. They show a straight 6 cylinder manifold and the primary is clearly towards the engine side of the manifold. Well the Weber/Holley I have is mounted with the primary on the opposite side. Not sure it matters except the linkage I have pretty much dictates the orientation. Any thoughts?

On the valve lash I set the valves to .018 which is the recommended lash from Isky for the cam I have which is a 264 cam. It's clearly in the instructions to set them to that setting. I set the lash using the running method which seems to work pretty well once you get the feel of it. I had them looser for the break in period and they certainly quieted down after my adjustment. I could goof with it some more.

The timing suggestion is a good one but I think I'm on the trail of this PCV thing. I hope that I was just using the wrong one. The one that seems to be causing problems seems new and is loose inside as it should be but I know you are supposed to have the proper valve and it may not be. This kind of makes sense to me because it seems slightly intermittent as sometimes I would drive it and it wouldn't do it as much. Almost like the PCV was either stuck or not in the position for it to cause my problem.

Oh also Dan on your question about the riser. I don't have the heat riser from the exhaust hooked up right now due to all the fiddling I'm doing. I just have the upen Weber air cleaner and element which I know is not correct. I will be putting the stock air cleaner back on when I figure out this problem. I think I misread your question.

Sorry so long.

Thanks.

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Sweet Emotion

Plugging the pvc valve will block some air flow. This will be most obvious at idle. It can mask some lean idle problems in the same way that the choke does when the engine is cold. Plugging the PCV valve is not a solution, but rather another indication of the nature of the problem.

Here are some suggestions:
The PVC could be missmatched for the carb. (this is tough to diagnose when you are using nonstandard parts)
The idle mixture could be adjusted too lean.
You could have a vacuum leak.

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1980 Aspen 225 super six

The PCV valve needs to see manifold vacuum at all times.
This doesn't make sense. The heat riser isn't really something you can have "not hooked up". The possibilities are: Present and working, present and stuck, absent. The heat riser ("Manifold heat control valve") is, as you identified earlier, the valve on the shaft that you can rotate by turning the round counterweight that is on the forward face of the exhaust manifold collector.

Dan,

On the Weber/Holley 32/36 progressive carb the secondary is closed until hard acceleration. Since the PCV inlet is below the butterfly valve on the carb base adapter then I would guess it's seeing manifold vacuum. I will see if I can get a vacuum reading on it tonight when I get home.

As to the riser, I appologize. My first answer, as you indicated, applies. Yes the manifold heat riser is indeed hoked up, in place and operating correctly I think. One question about the coil spring in the forward side. Is that spring for tension only or is bi metalic and expanding when heated? BTW I also have the little spring tensioner on the aft side of the shaft.

As to the PCV I also noticed the inlet brass adapter I have in there is a little loose which may be a cause of a vacuum leak there. I agree that plugging the PCV is not the solution. It's just is a tool to help me get to the botton of the problem.

Thanks

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Sweet Emotion

The coil spring is thermostatic, yes. Once things are good and hot, the valve should stay in the "heat off" position until it cools down. It takes a lot more heat to get these '71-up valves with the round counterweight to stay in "heat off" than it did the '70 and earlier ones!