Carter AVS running/starting issues

[Sir Dodge alot]

Hello gentlemen, apologies for pestering the members on this forum again so soon.

I would be grateful if you can shed some light on what may be wrong with getting the Carter AVS to work with my motor.

Yesterday I replaced the Lifter valley pan and converted from a 2 barrel manifold to a 4 barrel manifold, casting #2806301.

I have acquired a Carter AVS #4635S
To mount on said manifold.

Vehicle; 1964 Dodge Custom 880

The car will/may not start unless I dump half a cup worth of gas in the venturi.

If it does start it runs rough, badly shaking and will die if I do not keep revving it.
(And has a hard time re-supplying fuel to the bowls/accelerator pump)

I have done the listed minor tweaks.

Transfer slots have been adjusted to make a "square hole" past the butterfly flap.

main discharge nozzle check ball/needle was stuck. Cleaned. Moves freely.

Carb has been rebuilt,
(Float settings copied over from uncle Tony's carb specs)

Set float drop to 1 inch
Set float level to 7/16

Idle mixture screws set 2 turns out of seat

Air bleed screw (above idle mix screw) set at 1 turn out of seat.

Vacuum ports temporarily blocked off except brake/pcv hose.

Previously when the 2 barrel was on the car, the initial is set at 18 BTDC.

Manually controlling the choke valve when and if it starts.

Currently I'm letting the starter rest, it is hot to the touch.

Much appreciated and thank you if you can talk down to an idiot like me in layman's terms.

 

[413]

Turn the idle speed up a few turns and see if it keeps running. Then adjust from there.

Where is the hose that goes to the choke pull off? Is the fitting open? Look at right side front corner for this fitting.

Your carb had the right front ear welded, did this damage the carb? Is the base flat so no vacuum leaks?

 

[Sir Dodge alot]

I'd like to say no vacuum leaks, but the engine will not start and keep running without my persistent intervention.
(I.E keeping the choke closed and dumping gas when necessary)

Yes- the choke pulloff connection is plugged off.

The carb has been repaired/welded at an unknown date.

 

[413]

Ok thanks. Vacuum leaks usually make the idle high, not low But I wanted to ask.

does the accelerator pump squirt fuel?

 

[Sir Dodge alot]

It didn't at first, I cleaned the needle valve/check ball. And it squirts but after using up the gas in the accelerator pump well, it does not re-supply with fuel.

I manually have to remove the airhorn to uncover & dribble fuel into the accelerator pump well for the pump to squirt again.

Another small detail is the fuel level is always abysmally low in the bowls, making the floats drop to their full extent.

Fuel pump works, (unknown PSI)
2 barrel carb on it a few days ago idled fine.

 

[413]

Fill the carb through these vent holes. Don’t take the top off.

make something that will fit in there without spilling fuel all over the top.

no wonder it won’t run, it’s empty of gas.

 

[Sir Dodge alot]

Ok, will refill fuel through those holes.
Be right back.

So I noticed this issue before but if I fill the fuel full in the bowl.

It dribbles out the gold secondary booster/venturi? Creating a potential flood no start.

Starts STRONG but slowly idles down and dies (because of fuel starvation?)
Stayed on for 7 seconds.

Carb just doesn't seem to be refilling with fuel to meet the demand of the motor.

Secondary door opened strongly on a high rev, at least the air door is adjusted properly!

Update: I took the fuel feed hose going to the carb and stuffed it inside a plastic bottle, cranked the engine and no fuel was pumping up! How did the fuel pump fail right now out of nowhere?!

Absolutely strange.

 

[Sir Dodge alot]

I guess In the meantime, I'm swapping to my Old fuel pump I had few years back and see if it can pump fuel.

 

[57fury440]

Make sure you have fuel in the tank.

 

[CBODY67]

Fuel pumps do not last indefinitely, especially once the diaphram has been exposed to ethanol'd fuels and then allowed to dry out. Once dried-out, the disphram will become brittle and fail, from what I've read several places from good knowledge sources. Getting a new fuel pump AND quality fuel pump push rod can be key in getting things to work correctly.

You do not need to fill the float bowls "to the top", which results in fuel coming out of places it should not come out of as raw fuel. Put a bit less in them and stop filling BEFORE they start to dribble out the venturies.

18 degrees BTDC can be a little bit too much, but 15 degrees BTDC can work.

Enjoy!
CBODY67

 

[Sir Dodge alot]

@57fury440 yes, gas is present at the tank, at full capacity.

 

[Sir Dodge alot]

@CBODY67 I followed a guide online where this gentleman named Tony from uncle Tony's garage, he called it power timing, hence why the timing is at 18 BTDC.

That's the thing, fuel was already abysmally low in the bowls, and if I add a bit more it starts pouring out, makes me think a check valve is out of place...

 

[CBODY67]

"Power Timing" (by whateer name) is advancing the base timing until trace rattle (or worse) starts to happen, then you back-up the timing to where that does not happen. Basically, as much timing as the engine will take and run without detonation. It can vary from engine to engine, too. BUT also consider that on his engine dyno, Nick (Nick's Garage, YouTube) usually gets the most dyno power at "lower 30s" than higher 30s. The dyno puts more load on the engine that a moving vehicle does, usually, so that might explain the differences?

BUT, with most Mopar distributor calibrations, 18 degrees BTDC base timing will usually exceed the generally-accepted 40 degrees BTDC total advance for "best power", from what I've seen. So, best to check the timing (at 4000rpm or so) with the vac advance unhooked and using a quality dial-back timing light to actually see what's happening.

Another deal involves the heat range of the spark plugs being used. Elevated base timing can make the plugs run hotter, so you might also need to "read" the plugs for overheating. On our '66 Newport 383, with the max stock timing curve, 15 degrees BTDC resulted in 40 degrees total advance. It ran well there, with the stock J-14Y plugs and caused no problems, with the stock timing being 12.5 degrees BTDC. But, just knowing it was "just a bit better" than what it should have been counted for something, back then. Also, we always ran Premium fuel in that car, as it always clattered on the normal Regular of back then.

One side issue . . . IF you might get another 10 horsepower out of the engine at 18 degrees BTDC rather than 15 degrees BTDC, by the time that 10 horswppwer (at the flywheel) gets back to the road, it's more like 8 horsepower, and that much CAN count in a head-up drag race (with experienced drivers who "cut a good light") but for little else in normal driving. AT the peak horsepower rpm.

To me, if you are crusing at 50mph in high gear, then floor the throttle (for passing gear) on an automatic trans vehicle, as the trans downshifts into 2nd and the rpms head toward 4000rpm at WOT before it upshifts into 3rd at about approx 4500-5000rpm, FOR THE FUEL YOU ARE USING (or can pay for), if not clatter under those conditions, you might advance the timing a few degrees over the stock spec and see how that goes. You might advance the timing until you hear detonation right before the upshift occurs, than back it back about 2 degrees from there and re-test. If quiet on the re-test, then that's can be your "power-timed" initial advance setting. BUT if you put less-octane fuel in the vehicle, then you need to time it for the lowest-octane fuel you use, to keep everything quiet.

As secondary test, to check for the vac advance aspect of things, is to be cruising at a similar 45mph speed, then suddenly open the throttle to 1/2 throttle. If no clattering is heard, that's good. If you do hear clattering, then if you have an adjustable vac advance unit (internally adjustable), then you can tighten the spring adjustment to decrease the amount of vac advance at that particular level of intake manifold vacuum.

NONE of this is arbitrary "set it here . . . ", but is fine-tuned to YOUR engine, vehicle, and the octane of the fuel being used.

From my experiences and observations,
CBODY67

 

[Sir Dodge alot]

Wow that's alot of information @ Cbody67!

I was experimenting with light springs (Mr. gasket 925B) on both dizzy spring slots.

Have other spring sets (Mr. Gasket 928G) but it's a bit heavier, and makes the car sluggish from a stop light.

Forgot, I used to use a 1 inch carb spacer for my Stromberg WWC it increased torque at an upper RPM range. 1500 RPM?

It doesn't detonate on 93 octane, I surmise that the low compression on a 361 is keeping detonation at bay?
I used to have the initial at 22* no detonation there just hard starting, so I bumped the initial down to 18 where it is now and no more hard starting.
(Kicking back at the starter)

I'll check the timing again as you say at 4K RPM once the motor is running again.

The stock distributor in the car right now has 11.5 of advance, quite plenty enough and the distributor bushing is not worn, so I may keep this dizzy for a while.

 

[Sir Dodge alot]

Update;

I put in an older fuel pump that was original to the engine, no good, the fuel pump is dead on this one also.

The fuel pump push rod didn't have any abnormal wear, so no need to replace that I believe.
Not to mention the allen key to remove the fuel pump push rod won't loosen!
(if it ain't broke, don't mess with it!)

Main issue is fuel, now I know why the motor won't turn on.

Next month or so I should have enough funds to get a fuel pump.

Hopefully then the engine will start and idle on it's own power!

 

[Sir Dodge alot]

Appreciate the assistance gentlemen, I think I now have a fighting chance on making the 4 barrel work.
#Excitement!

 

[Sir Dodge alot]

Another update; the fuel pump failed, and most likely the fuel pump push rod may be worn also.

It's an original fuel pump pushrod.
Engine has 97K miles on it.

Dunno about the lifespan a fuel pump pushrod would last for, I'll source for pushrod from either Hughes engines, Comp cams, Mopar performance, or NOS.
Just to leave this out here... fuel pump pushrod should measure 3.220.

 

[Sir Dodge alot]

@CBODY67 Or anyone that can answer this question, a bit off topic.

Have you ever seen an original fuel pump pushrod worn down before?

 

[Sir Dodge alot]

Update again hopefully a tip, few days ago i was smelling fuel as i was driving, i chocked it up to the carb A/F mixture needing adjusting again, Then shortly few days after. The fuel pump died.
Coincidence? I think not. So if you smell fuel, do inspect your fuel pump, and expect your fuel pump to fail imminently.

Another thing, Your fuel pump push rod rides on an eccentric on your cam and pushes on the fuel pump lever/arm and pumps fuel, (Like a hydraulic tappet, in this case fuel not oil)

So if my thinking is correct you should be using high ZINC content oil in your engine like Diesel oil like I do. (15W-40)

Zinc will lessen the wear on your bearings/mains/tappets/
Really anything that rides against an oil film. (Fuel pump pushrod included also)

Hope that's some food for thought.

 

[57fury440]

Fuel pump pushrods do wear down. I have only come across this on high milage motors. If you suspect that it is the pump or the pushrod you could buy a cheap low pressure electric fuel pump and do a temporary hock up to see if that solves your delivery problem.