Stalling at stop light

[FL.40]

Ladies and Gentleman, I have an issue that I would like some help on.

I can start my 351W with ease, and it will idle and run with the best of them.

When I am cruising down the street and push the throttle farther than I should, it runs great.

But when I come to a stop light , if I don't pull up to the stop lights correctly, ( down shift, give the motor time to settle down and get into a good idle) the motor will want to die.

I took it out last Saturday(for example), let it warm up for about two minutes, drove down my street( 1/4 mile maybe), took a right and drove about 1/2 mile to the major(6 lane) thorough fair, and stepped on it pretty good, up to maybe 50 mph. I got about 1 mile down the road and came to a stop light. Shifted into neutral and coasted to a stop. Motor died and I couldn't get it restarted and had to push it off into a nearby business driveway.

This has happened before before and I have been able to get it restarted with out too much trouble. On Saturday I drained the battery trying to restart and I called my neighbor to come a give me a jump. Once I opened the hood I noticed the fuel filter to be almost empty(I have the clear plastic one) and what fuel that was in there was bubbling. Not in a boiling way, more like a gulping air way. (if that makes sense) After approximately 15 min, the filter filled and a jump from the neighbor, I was able to restart the motor.

I have changed the fuel pump, filter, fuel lines( rubber and steel) and sending unit, from the gas tank all the way to the carburetor.

After all this explanation, I am at a loss as to what the problem is.

I hope one of you fine people can help with this. I can not think of anything else to check, replace, adjust to help.

Thanks for you time. Jeff

 

[JimNiki]

if I hadn't read the whole post, I would've said... carby. As a quick test, increase the idle screw about 150 rpm and try to replicate the issue. This test will only confirm that the issue may be carby related, not neccesarily idle adjustment related. Could be mixture, vacc leak, etc.

 

[imusa76]

spray some carb cleaner around the base of the carb, if the RPMs change as you spray, its a Vac leak.

I had the same issue, and it ended up being the alumium spacer block under the carb, I had it stoned to level it, and the problem went away.

 

[matrixx]

Yep, sounds like a vacuum leak, might be fine when its cold but expansion or heat could cause something to loose seal. Are your fuel lines away from high temp areas? Might be vapor locking if your fuel is bubbling and not flowing.

 

[caspianwendell]

Do you have a vacuum gauge?

 

[TommyK]

Could also be a venting issue with the gas tank.

 

[FL.40]

Gents, my apologies for the long time since asking the question. But I finally got to work on it. Saturday I pulled the tank and checked the vent tube on top of the tank and it looks fine.

I then sprayed the base of the carb and the rpms did drop. So I purchased a new base gasket and that helped but it is still not perfect.

While I test drove it I noticed if I drove real conservative it was fine , for the most part. But when I got on it, it would wants to stall.

I got home a let it idle in the garage and after a few minutes , I noticed the fuel level in the filter had dropped. Instead of full, it showed about, maybe less than half of the filter. It started to stumble and slowly died.

So thanks for getting me this far.

Jeff

 

[VegasFastback]

That sounds like a fuel pump

 

[rutkak]

You had me at vacuum leak. I've had a leak in just about every possible place and I'm a newbie compared to some of the Pros here. Glad to see you worked through that.

I'm with Tommy on the latest issue...Try doing the same with the fuel cap off or open to make sure it's not a venting problem.

Is it the original engine? Did you remove the emissions canister and plug the vent or anything? I've lived that pain.

-KR

 

[wwhite72]

Rear bowl floats are set too low.

 

[72HCODE]

Is this a holly carb or edelbrock?

The holly is notorious for stalling on heavy stops due to fuel bowl design.

Assuming it is not a vacuum leak which is still possible. You can raise the fuel level inside the bowls. They recommend the fuel just touches the inspection hole floor of the fuel bowl, however in some cases you may want it even higher.

You can also try opening up the idle air bleed screws this will richen the idle and may help when the engine suddenly drops Rpms.

You can also raise idle Rpms. Set the idle Rpms with the car in gear. Some cars drag the Rpms down alot when in gear verse park or nuetral. For example my car requires the no load idle set slightly over 1000rpms because in gear it drops under 800rpms. Mine will stall if I attempt a factory setting of 625-650rpms. Took me years to find a happy place for my wacky engine combination.

Basically I aimed for as smooth an idle as possible with the car in gear foot on the brake, with headlights on. If you do that and after 20 seconds the idle gets noticeably rougher and you feel the car is bouncing then you will need to possibly open the idle bleeds or raise Rpms.

The fuel bowls should be checked first to make sure it isn't low but if you open the inspection cover and fuel comes flying out then you know you can't raise the fuel level more and you need to look at idle Rpms or air bleeds. If the fuel level is too high in the bowls on heavy breaking fuel may shoot up the vent tubes flooding the motor and stalling it again.