Bogging on hard acceleration

[shadango]

So my son rebuilt his slant 6 carter BBD two BBL a couple weeks again and all has been fine including a 4 day road trip....several hundred miles.

Last afternoon itvstarted bogging on moderate to hard acceleration .....it runs fine other wise.

Stab the pedal and it bogs and sometimes stalls.

Seems like accelerator pump to me and I told him to check the setting, and open it up some if it's still at the "correct" setting.

No other issues that we can find yet. Fuel filter was changed before the trip.

Any thoughts on this ?

He goes away to college with it in just 3 days .....don't want him to have issues while away at school.....

Thanks for any help folks.

 

[shadango]

Well, he says the accel pump is set according to spec...and that it has no more adjustment to make it longer (more fuel)....

 

[XfbodyX]

See if the dizzy moved or mark it and inspect the drive gear.

 

[volare 77]

what was the color of the accelerator pump cup?

 

[BudW]

Two most common things that causes a bog: Too much fuel or not enough fuel.
Vacuum leaks and ignition timing come in as next two common items.

The accelerator pump is needed to give the engine a short burst of a slightly richer mixture (for power) and as a “makeup” when carburetor is transiting from idle/off idle to the main fuel circuit (the center booster venturi's.

To check the accelerator pump circuit – a person needs to remove the air cleaner cover and open the choke valve (a screwdriver holding it open will work). With engine off, move the throttle valve open a moment and check for a pair of pencil lead size streams shoot out into the center of the venturi’s, immediately after touching the throttle and stop after moving the throttle.
It helps to have a flashlight/shop light looking down and/or a helper to view.

The same thing if engine is running – but in that case, a screwdriver to hold choke valve open is not needed (nor recommended).

The older Carter BBD’s, a person could push down on the accelerator pump piston and check its operation, but the newer versions (one that comes on FMJ vehicles) – that is inside the top cover and not easily accessible.


The rod marked with red arrow is your accelerator pump arm. When you move the throttle open, you should also see that arm move as well (in relationship to throttle).

What I suspect might have happened is a screw has loosened. Inside the top cover, the arm has two different adjustments. One is for accelerator pump and other is for power valve. If either screw has loosened or is misadjusted, it will cause a bog.

Blue is the accelerator pump and orange is for the power jet/metering rods.

The levers inside (pump arm and rod lifter) that screw onto the arm can be made from plastic (most are) and sometimes can have loose screws.

There is an official procedure to adjust both levers – but it is a pain sense there is not a lot of room to work in that cavity.
BudW

 

[shadango]

Thats exactly what the son did today -- looked into the carb as he worked the throttle.. and says he sees no gas squirting.

So, he is gonna pull the carb off first thing in the morning and pull the top half of the carb off and see whats up.

It was a brand new carb kit.....could the diaphragm have gone bad just like that?

Where do you guys stand as far as reusing the felpro base gasket and the airhorn gasket? He actually has another airhorn gasket from another kit he already had (older kit) as well as another diaphragm....but not a base gasket.....we are using the thick felpro deals as opposed to the thin ones.

 

[XfbodyX]

Fuel Pump Condition?

 

[lowbudget]

Check to see if the accelerator pump cup rolled. I had that happen to me. My Mopar guru buddy said that happens sometimes when I told him about it.

 

[shadango]

Fuel Pump Condition?

It was brand new when we rebuilt the engine....about 8k Mike's now though.

 

[volare 77]

IIRC, the acell pump cup color should be green in color. There was a recall on them back in the late 70`s I believe the cup should be lightly lubed when installed.

 

[volare 77]

75 Dart Carb Problem | Moparts Question and Answer | Moparts Forums

 

[shadango]

IIRC, the acell pump cup color should be green in color. There was a recall on them back in the late 70`s I believe the cup should be lightly lubed when installed.

Would the color hold true even in aftermarket kits?

What should it be lubed with? Seems like gas would wash away any lube???

 

[volare 77]

Lube is for initial pumps while the carb is still dry. Once gas gets there it would be fine.

 

[volare 77]

1977 Dodge Aspen Recall for Fuel System, Gasoline, Carburetor System Problem #77V242000

 

[shadango]

Lube is for initial pumps while the carb is still dry. Once gas gets there it would be fine.

Would sylglide work or something like vaseline??

 

[shadango]

IIRC, the acell pump cup color should be green in color. There was a recall on them back in the late 70`s I believe the cup should be lightly lubed when installed.

The color of the one we are using now is yellow cup part, red core...came in the kit....and it is very deformed.

 

[shadango]

The son put it all back together using a new pump from an old kit we had on hand....green in color.....

He says it still seemed to hesitate some and then he tweaked the setting and now it's ok.

 

[BudW]

Someone got in a hurry when it was assembled.

What lube to use doesn’t matter much. Gas or engine oil will work. Never tried Vaseline (which is what I use for transmission lip seals and check balls) for this - but no reason it won’t work. The “cup” needs a liquid presence for it to get primed with gas. Once that happens, all is good.
Without some liquid, it will take many pumps before accelerator pump gets primed.

Also, a bit of liquid/lube helps to prevent the problem you have with current accelerator pump piston cup.

If I was there, and if you removed the carburetor top only, I would have pulled the engine dipstick and gotten a finger tip worth of engine oil to wipe on the cup.

Glad problem is fixed. It wasn’t exactly what I thought was wrong – but close.


Vaseline works great for automatic transmissions because it will dissolve in the transmission fluid. If a person has ever fought with check balls in a valve body (other makes are even more of an issue), a touch of Vaseline on the check ball will allow it to be suspended upside down without worry of it disappearing.
BudW

 

[shadango]

Someone got in a hurry when it was assembled.

Well, that crossed my mind.....but he drive the car for 1,000 miles since the rbeuild and it was fine...just started doing it one day.

Does anyone know if you can buy JUST the pump itself and if so the green one specifically?

Looking at pics of all the kits on rock auto and the chain stores, they are all sorts of colors.

Also, our kit came with with I believe is the "power valve"....and it is referenced in that "75 dart" link above.....the carb we are working with doesnt HAVE that........or are those for the v8s only?

 

[volare 77]

There was some of the pump recall cups on ebay a while back. Don`t see them now. I found a plunger on ebay but I don`t know what this one fits.
4267129 Plunger, OEM NOS Mopar Dodge, Free US Ship ~ | eBay