Engine bogs when accelerating from a cruising speed.

[48ply1stcar]

I have read about this problem until eyes hurt.  When I get to the end of a post the answer is not there.  I have seen the little dizzy wire mentioned as a problem and I think it solved Mr. Daddyo23.

I have disassembled, cleaned, and reassembled both the distributor and carburetor.  Little dizzy wire was intact with continuity.  Zero ohms, but I can't remember if I disconnected the wire when I measured it.

The breaker plate moves when I apply vacuum, but does not hold, leaks vacuum.  Also would this affect the carbs vacuum piston and step up rod? vacuum passage in the carburetor?

 

I can drive the car at a reasonable rate until I get to 50 mph.  The engine bogs when I accelerate from a cruising speed, 50 or at the end of 2nd gear 25 -30 mph.  The engine feels like it's flooding when it bogs and I have notice that the carburetor horn gasket is damp.  Last week I replaced the float with a float that floats, and that the needle is closed properly.

 

Has anyone had this issue and solved it? 

I guess I might have to bite the bullet and buy a vacuum advance after I try a full out carburetor rebuild.

[linus6948]

You can get a rebuilt vacuum advance unit for $69.50 from Andy Bernbaum, I did and it made a world of difference for my car.

https://www.oldmoparts.com/parts-electrical.aspx

[FlashBuddy]

...or put a drop of oil on the accelerator pump, it might be dry and not pumping. Me too! All the reading only to find the OP has gone holo holo. For me I just have to take an educated guess, perform the maintenance with finger's crossed. If I were you I would sort out the vacuum leak and decide what next after that.

[48ply1stcar]

Good strong stream from the accelerator pump.  Reminds me of my youth.

 

When I was a kid we lived so far out of town I could pee in the backyard.  Now I can't pee that far.

 

[pflaming]

Pee? You can still pee? 

[justold]

1 hour ago, 48ply1stcar said:

I have read about this problem until eyes hurt.  When I get to the end of a post the answer is not there.  I have seen the little dizzy wire mentioned as a problem and I think it solved Mr. Daddyo23.

I have disassembled, cleaned, and reassembled both the distributor and carburetor.  Little dizzy wire was intact with continuity.  Zero ohms, but I can't remember if I disconnected the wire when I measured it.

The breaker plate moves when I apply vacuum, but does not hold, leaks vacuum.  Also would this affect the carbs vacuum piston and step up rod? vacuum passage in the carburetor?

 

I can drive the car at a reasonable rate until I get to 50 mph.  The engine bogs when I accelerate from a cruising speed, 50 or at the end of 2nd gear 25 -30 mph.  The engine feels like it's flooding when it bogs and I have notice that the carburetor horn gasket is damp.  Last week I replaced the float with a float that floats, and that the needle is closed properly.

 

Has anyone had this issue and solved it? 

I guess I might have to bite the bullet and buy a vacuum advance after I try a full out carburetor rebuild.

Have you checked fuel filter , fuel pressure and flow ?

[Plymouthy Adams]

you do not need the vacuum advance for acceleration, actually it is taken out of play by loss of vacuum when accelerating.  You can however plug the vacuum line if you feel the vacuum loss may be an issue.  As for me, I think I would look closer at the spring tension on the points, modern replacement contact sets are a bit light in the loafers in this department...point bounce or float whichever you like to call it is becoming more and more common 

[55 Fargo]

4 hours ago, Plymouthy Adams said:

you do not need the vacuum advance for acceleration, actually it is taken out of play by loss of vacuum when accelerating.  You can however plug the vacuum line if you feel the vacuum loss may be an issue.  As for me, I think I would look closer at the spring tension on the points, modern replacement contact sets are a bit light in the loafers in this department...point bounce or float whichever you like to call it is becoming more and more common 

The above post has good info.

You dont need the vacuum.advance as stated.

[Dan Hiebert]

You may not need the vacuum advance for acceleration, but if it's there it needs to work.  If it leaks you'll have those flat spots on acceleration. 

[48ply1stcar]

I have not check volume. I have it stuck in my head that either it's flooding (damp gasket around the horn or needle leaking) or that it's some secret thing nobody's sharing and they're waiting for my to sell the damn car for scrap. Plugs are sooty. Engine was rebuilt and I installed it last spring. I still haven't been able to get it running right. New fuel pump last year.  This week new fuel line to the pump, new fuel filter in-line before the pump. I do a volume test when I remove the carburetor again. I'll do a proper rebuild this time. Looking for any restrictions in the carb specifialy in the step-up area.  I did disassemble the Distributor and clean the breaker plate, really no-way for me to check the points spring.

[Lloyd]

Wet plugs would indicate flooding. But sooty plugs can be a rich mixture. Switching to a hotter plug may help, unless Plymouthy's suggestion concerning point float is right. Which would suggest that there is nothing wrong with the carb, its just not getting fire at higher rpm's.

So how do you check for point bounce or float?

 

Heres a troubleshooting page from the B&B service manual that may help:

 

(1) Black Smoke  from exhaust pipe and sooty deposit on spark
plugs caused by rich mixture.
(a) High float level. Reset to specifications (tables IV to XI,
pars. 28, 44, 61, 78, 95, 109, 124, and 140).
(b) Too large metering jet or a too small metering rod. Check
specifications (tables IV to VIII, pars. 28, 44, 61, 78, and
95). Replace jet or rod.
(c) Nozzle installed without a nozzle gasket, when one is
required.
( d) Metering iet or nozzle looae. Tighten jet or nozzle plug.
(e) Pump relief port clogged. Clean port.
(I) Air bleed hole (in air bleed nozzle) stopped up. Clean
nozzle.
(g) Hole in main vent tube clogged. Install new tube.
(h) High fuel pump pressure. Repair or replace fuel pump.
( i) Metering rod spring not connected to metering rod. Connect
spring.
(j) Clogged air cleaner (outside vented carburetor).. Clean.
air cleaner.
(k) Warped bowl cover or damaged bowl cover gasket (inside
vented carburetor). Replace bowl cover or gasket.
(I) Vacuum pasaage to step-up piston clogged (B-B carbtur
retora) . Clean passage.
(m) Wrong flange gasket used (B-B carburetora). Refer to
paragraph 113d (2) .
(n) Flange gasket leaking allowing air to enter vacuum pasaage
to step-up piston (B-B carburetor). Replace gasket.
(o) Step-up piston stuck in cylinder due to gummy deposits
(B-B carburetor). Clean piston and cylinder.·
(p) Two gaskets used under step-up piston, keeping step-up
rod from seating (B-B carburetors). Remove one gasket.
(q) Stretched metering rod spring (Y-S carburetor). Replace
sprng.
(r) Worn or ruptured metering rod diaphragm (Y-S carbu,retor).
Replace diaphragm.
(s) Passage to vacumeter cylinder blocked (WOD carburetor).
Clean passage.
(t) Vacumeter piston atuck in cylinder (WOD carburetor).
Clean piston and cylinder.
(u) Choke stuck partially closed. Centralize choke valve.
Repair or replace choke linkage and/ or choke control cable.
Repair automatic choke if used (par. 77).
 

Edited June 1, 2018 by Lloyd
Additional comment

[Plymouthy Adams]

1 hour ago, Dan Hiebert said:

You may not need the vacuum advance for acceleration, but if it's there it needs to work.  If it leaks you'll have those flat spots on acceleration. 

the man is trying to troubleshoot and suspected vacuum advance, thus the post that in acceleration it is not needed, one problem at a time.

[greg g]

One more item now that you mentioned sooty plugs and the step up.jet.  check the carb to manifold gasket.  There needs to be a slot that aligns with a hole in the carb base. That hole is the vacuum passage to the step up piston.  The default position of the piston is up pushed by the spring.  High vacuum during idle or part throttle cruise pulls it down closing the jet.  If it doesn't close you are getting an over rich mix.

 

I have seen carb kits with replacement gaskets with no slot so no vacuum, cut with one slot so you need to assure the correct position during carb installation, and some cut with four slots so even fools like me have a chance of getting it right..  The purpose of that jet is to follow on, supplying a rich mixture after the initial squirt from the accelerator pump.  It continues to richen the mix till the engine returns to high manifold vacuum condition.  If it is hanging open, the accelerator pump may now be providing more fuel than needed hence the bog right after going to WOT.  Don't know what scrap value is these days, but I'd be interested....

[48ply1stcar]

Thanks everybody for the information.  Definitely going to do full out good carb rebuild. 

 

[Young Ed]

Just now, 48ply1stcar said:

Thanks everybody for the information.  Definitely going to do full out good carb rebuild. 

 

let me know if you need anything. I've done a few of them

[48ply1stcar]

Checked fuel volume tonight, 4 ounces 12 strokes.  I have a in-line filter along the frame under the front seat.  Blocked fuel before the filter and blew out the fuel and and fuel pump.  I'll try another volume test from a gas can.  I haven't cleaned out my gas tank in about 20 years, so it could be do.  I'll blow out the fuel line to the tank and if that helps.

The newbie (JUSTOLD) gets a kewpie doll.

Edited June 4, 2018 by 48ply1stcar

[Lloyd]

That’s great you got it figured out. Thanks for posting the problem. 

 

[48ply1stcar]

1 hour ago, Lloyd said:

That’s great you got it figured out. Thanks for posting the problem. 

 

Not yet, we'll see tomorrow if that is the only issue.

 

[48ply1stcar]

UPDATE

 

No fix yet, fuel pump  issues addressed in other thread next is carb rebuild.

Also replaced the points, no difference.

 

Edited June 28, 2018 by 48ply1stcar
Info added