Car stalls when it's hot out.

[charger1970]

Here is my problem. When the air temperature gets above 70 degrees and when I’m at idle and then step on the gas, the car will stall or made a small pop and then loose acceleration. This doesn’t happen all the time when it is warm out, just more frequently. It runs great when it’s below 70 degrees. So my thinking is that it’s not the timing or floats. If the timing and floats were set wrong it would do the same thing when the air temp is colder. I’ve adjusted the idle mixture screw numerous times and this has no effect. I don’t think that it’s the fuel boiling because the engine is running at the same temp when the air temp is hot or cold. Does anyone have an

[MoparMarcIdaho]

under the intake?The factory puts those in there for a reason,also check the heat riser passage and heat riser if so equipped,if the riser is stuck it will make excessive heat under the carb when not needed.Since your problem seems to be heat related,do these things next,a cool can might be just what the doctor ordered too.

[charger1970]

What is a heat riser?

[MoparMarcIdaho]

if so you dont have one.If you have the stock cast maifolds,its on the passenger side,between the manifold and head pipe,basically a plate thats springloaded to restrict exhaust flow when cold to direct it through the passage under the carb until the engine warms up for cold weather.Need to know what carb and intake you have and what car its in.

[dwc43]

Sounds like you have accelerator pump trouble in the carb. May need a new diaphram or need to adjust it or a different squirter nozzle size. What carb you running? If it's a stock intake the heat sheild is still under there. It's riveted on and is not removable. The heat riser lets exhaust gas circulate through the stock intake to warm it up on cold mornings and then it opens after a certain temp and no longer works. The are known to stick. It's in the passenger side exhaust manifold right where the pipe bolts up. There's a weighted wheel on the side of it. See if you can turn it. If so, it's O.k. It may have already been removed if exhaust work has been done on it.

[charger1970]

I have a 670 Advenger carb and a M1 mopar intake. If i do have an accelorator pump problem what would I need to do to adjust it. More squirt or less?

[rumblefish360]

More squirt.
This can be done with a larger cam on the side of the carb. Basicly, you unscrew the holding screw and slide of the cam. Replace with a larger cam, screw the screw back on and test. They also sell larger accelerator nozzles. Save that for later.
The cams are color coded, plastic and flat. Sold in a package a several. There rate of discharge are on the package. (Or should be)

[charger1970]

Don't you just lenghten the accelortor pump stroke?

[rumblefish360]

That would be for a Carter, not a Holley. Though, not all, but most have other holes to use in the cam.

[charger1970]

My pump has a spring with two nuts on a threaded bolt. If you loosen one nuts the spring get longer or shorter and I thought that was the way you adjused your pump. On a edelbrock there are holes to move the pump arm. Or am I wrong?

[rumblefish360]

My pump has a spring with two nuts on a threaded bolt. If you loosen one nuts the spring get longer or shorter and I thought that was the way you adjused your pump.

Not on the Holley. That is an adjustment that should not be done and left alone.
The pumpshot for Holleys are done at the cam on the side. Squirters can be purchased to change there hole size out.
On the Edel./Carter, you move the arm closer to the piviot point. Correct. Also, there are squirters you can purchase to change the size hole the gas squirts from.

[MoparMarcIdaho]

positive movment,that is when you move the linkage the pump moves with it,you shouldnt have to lengthen it any.I think the book says go to WOT and set gap at 20 thou.

[charger1970]

So if i'm not getting a big enough squirt on the acc pump, wouldn't I have the same problem when I'm driving at any temp?

[MoparMarcIdaho]

it would be worse when the motor is cold,not better.

[ttraut@unlockit]

This SOUNDS like a too lean condition. I'm not a carb guy but I remember playing with my Thermoquad adjusting the metering rods until I got what sounds like the same condition: a pop and no power. When I adjusted the metering rods for more fuel, I was fine.

Terry

[dwc43]

Yeah, it's just that there is not enough extra fuel when opening the throttle. Cams can make the pump shoot more and make it las t longer. Also a smaller squirter will make a big pump shjot last longer where a larger squirter will make it last less, but give a larger amount of fuel all at once. It just depends on what the engine combo needs to get it to come off idle just right.