Weber 32/36 Water Choke - Idle Bogs Down Post Full Throttle

[Santawillis]

Hello everyone,

 

I'm facing an issue where my car stalls whenever the RPM falls back to idle, this occurs right after the second barrel of the carburetor activates. To get it to idle properly again after startup requires quite a bit of tinkering from my end. Surprisingly, if I avoid heavily pressing the throttle, which is somewhat disappointing yet still enjoyable, the car operates smoothly and maintains a stable idle (slightly below 1,000 RPM for me currently).

 

I've already taken a few troubleshooting steps:

1-Verified that the carburetor is receiving a steady 12 volts.
2-Disassembled and meticulously cleaned every jet.
3-Checked for and found no vacuum leaks.
4-Adjusted the carburetor about three times, but the issue persists each time.

I'm at a bit of a loss here and would greatly appreciate any insights or solutions you might have to offer.

 

Thanks in advance,
Rafael

 

Edited March 31 by Santawillis

[John76]

What's the condition of your coil?

Sounds like it is being over-taxed trying to light the fire on a rich mixture when the secondary opens.

Just a thought ...

[Mike Self]

One thing  you can cross off your list:  a water choke carb doesn't need electricity unless you have an electric idle jet solenoid.  It shuts off gas flow to the idle circuit when you turn the engine off, to prevent dieseling.  

 

If you do have one of these, with the ignition on, disconnect the wire from its terminal; you should hear a distinct click.  No click = dead solenoid--or at least one that isn't grounding properly.  But if you don't have an idle jet solenoid, then your problem lies elsewhere...

 

mike

[TobyB]

Quote

whenever the RPM falls back to idle, this occurs right after the second barrel of the carburetor activates

 

So you mean, when you go play, use full throttle, then come to a stop, the thing won't idle?

 

That suggests you ought to make sure the second barrel's closing fully after opening,

and that's not too hard to do with a light.

Because it sounds like the 36 flap's getting stuck open a bit, and the car doesn't like idling on it.

 

first guess,

t

 

[Santawillis]

8 hours ago, Mike Self said:

One thing  you can cross off your list:  a water choke carb doesn't need electricity unless you have an electric idle jet solenoid.  It shuts off gas flow to the idle circuit when you turn the engine off, to prevent dieseling.  

 

If you do have one of these, with the ignition on, disconnect the wire from its terminal; you should hear a distinct click.  No click = dead solenoid--or at least one that isn't grounding properly.  But if you don't have an idle jet solenoid, then your problem lies elsewhere...

 

mike

I do have one of those buggers, disconnect them and the car does not want to start at all which makes sense... Ignition on and I hear a "zap" sound but no necessary a click. This may be it!

[Santawillis]

8 hours ago, John76 said:

What's the condition of your coil?

Sounds like it is being over-taxed trying to light the fire on a rich mixture when the secondary opens.

Just a thought ...

Coil is in good shape! Tested that as well!:)

[Stevenc22]

When the engine is warm, are the choke plates fully opened at all times? they should be.

Edited March 31 by Stevenc22

[Santawillis]

1 hour ago, Stevenc22 said:

When the engine is warm, are the choke plates fully opened at all times? they should be.

Yes, engine is warm the choke plates are wide open so the choke is working I would assume.

['76mintgrün'02]

This is a fun one (for us).  

 

Have you pulled the idle solenoid out and had the fun of watching the little needle move with 12v added?  I've got photos from when I did that, posted and reposted in old threads.  It'd be even more fun to follow along with this one if it had photos too.  I've found stuff in my photos that I've missed while under the hood.

 

I'm trying to imagine how hung-up linkage might cause this issue.  The loose-link connection is pretty simple, but the fast-idle choke-cam can get finicky.  

 

Remember what Mike's father-in-law taught him?  90% of your fueling problems are in the ignition.  Do your full-throttle runs also include higher rpms?  The advance mechanism may be hanging up on its way back down, throwing-off advance at idle.  

[John76]

It sounds like you covered all the basics as evidenced by the primary circuit performing correctly (idle jet (solenoid), choke, throttle linkage, vacuum leaks, ignition, etc.)

Your problem starts after the secondary is opened (and closed).

 

Concentrate on what happens when the progressive secondary kicks in to supplement the primary:

 

- Pump jet squirts gas only into the primary on a Weber 32/36 ... unless your carb is fitted with a sync linkage.

-Secondary main, air corrector, idle jet and emulsion tube kicks in.

- Float drops, opening the float needle to refill the bowl.

- Manifold vacuum drops, thus eliminating the vacuum advance on the dizzy.

- Coil is firing rapidly (charging and discharging). 

- Engine is calling for more air through the air cleaner.

- Engine is calling for more fuel from the pump and tank.

 

Your engine may be flooding, causing it to stall after the secondary is opened. This may explain why it starts after sitting for a while, letting the gas evaporate from the intake manifold.

Things I would check:  Float level, bad float (plastic or brass?), fuel pressure, fuel filter (at pump and tank), fuel hoses, missing or incorrect secondary idle jet, clogged air filter, all connections from the coil to the dizzy, points and condenser. 

Just to rule out ignition problems, can you replace the coil and condenser with known good components?

 

 

1 hour ago, '76mintgrün'02 said:

  90% of your fueling problems are in the ignition.

Yep...Messrs Weber would be proud of @Mike Self's father-in-law!

This is an interesting problem.

If the centrifugal advance is sticking (in advance) after the secondary closes, your idle speed would increase.

If it was sticking in the static position, your primary driving would be noticeably horrible.

 

 

 

 

 

[Santawillis]

Update: I was finally able to test the solenoid and it did operate normally once 12V was applied. I also did a deep clean on the solenoid. Once the weather improves, I will give a test drive a shot!

 

@'76mintgrün'02 Definitely a good call on checking the connections, I made sure all was lubricated!

 

Rafael

[Santawillis]

Final Update : Looks like the solenoid was the issue, idle is still low after spirited driving but it now holds idle. 

 

Rafael