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Unread 11-25-2011, 01:07 PM   #1
Fernando
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Weber 32/36 floods on startup, what do I adjust?

Hi everyone
I have a Weber carb 32/36 and when the engine is cold, like first start in the morning, it runs really rough, lots of black smoke at the tailpipe and ignition misfires... it's obviously flooding for a couple minutes, I have to give it gas and hold it at around 1500 rpm for a couple minutes and it gets better, once warm I have no problems...

I have a FPS but I must admit it may not be working right, however I hate those regulators I would like to know if there is anything I need to adjust, I have the proper air and fuel jets and jeep was running perfect until a couple weeks ago, so it's not a jetting problem.

I thought that maybe adjusting the float could help but I do not know how to do this would need instructions, also it's strange that it was working fine and suddenly now it sputters on startup.

Thanks for the help, I can give my jet values if someone wants to know but I am sure they are right and recommended by mcmud who is a Weber authority on the forum.

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Unread 11-25-2011, 10:51 PM   #2
Fernando
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Originally Posted by JeepHammer
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Unread 11-26-2011, 08:40 AM   #3
superj
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it sounds like your choke is working really well. because once it warms up it is fine. how is your choke set up? manual or electric?
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Unread 11-26-2011, 10:13 AM   #4
mcmud
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Hello Fernando,

Lets first verify that the choke pull-off is operating as it should, at the startup, manifold vacuum should pull the choke plates open to a preset stop, just a tad shy of 1/4" off of the airhorn walls. You'll need to remove the propane injection bonnet to view this process..... let us know what you find.
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Unread 11-27-2011, 09:30 AM   #5
Fernando
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Hi Terry!! Thanks for showing up! My choke is not working, I did what you told me Yesterday I ordered a manual choke conversion kit, I would like to convert it to manual operation, this is what happens: It does bring the plates to a preset stop but will not hold them there, as soon as I start the Jeep the plates begin to open in about 30 secs they are fully open... I guess I have to fix the choke before making any other adjustments but I don't know what to do other than replace it for a manual.

superj I don't know what you mean that the choke is working really well... maybe you meant the opposite?

Anyway thank you guys, Terry if you know how to adjust or test this electric choke please let me know, I'll be working on the Jeep today!
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Unread 11-27-2011, 11:58 AM   #6
superj
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Yes, I was saying it in jest.

It sounded like the choke was not opening but if checked it and it's opening to soon, maybe the heated spring in the choke housing has come loose or the housing it's self has spun?
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Unread 11-27-2011, 12:04 PM   #7
mcmud
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Always my pleasure to hear from and or offer help to you, my friend

Lets review, if at the attempt to cold start, you cycle the throttle to prime and set the choke plate fully closed, then at the start the plates are immediately drawn to the preset and then the bi-metal spring fully opens the plates too soon... its an EZ fix.

Loosen the three retaining ring screws at the bi-metal spring cup and rotate that cup counter-clockwise.
How much would depend on ambient temps, enough so that the plate would not completely open until at least four-five minutes after the startup, a bit more if you desire.

Let me know how this works out for you.
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Unread 11-28-2011, 08:24 AM   #8
Fernando
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Thanks Terry, here is a detailed review of what is going on...

I cycle the throttle to prime and the choke plates travel to the fully closed position

I start the engine, fires right up, then after about four seconds, the revs drop and Jeep starts to struggle and misfire, black smoke starts coming out from the exhaust.

I step on the gas the help the engine and the choke plates open fully as soon as I step on the gas, no more than a minute has passed since startup.

The part that leaves me wondering is why is the carb flooding... the choke plates remain closed until I touch the throttle, I only touch the throttle because the engine is struggling so bad I am afraid to foul my plugs because of the excess fuel...

Thanks Terry, any adjustments you suggest I will perform tonight, yesterday I cleaned my air filter, the crankcase breather filter and fixed a problem with the power door locks I installed on the Jeep, I did not touch the carb yet, wanted to give you more information before starting adjustments.
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Unread 11-28-2011, 10:25 AM   #9
mcmud
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Quote:
Originally Posted by Fernando View Post
Thanks Terry, here is a detailed review of what is going on...

I cycle the throttle to prime and the choke plates travel to the fully closed position

I start the engine, fires right up, then after about four seconds, the revs drop and Jeep starts to struggle and misfire, black smoke starts coming out from the exhaust.
At the initial start and without applying any additional pedal, are the choke plates being drawn open approx. 1/4" off of the airhorn walls?

Quote:
I step on the gas the help the engine and the choke plates open fully as soon as I step on the gas, no more than a minute has passed since startup.
With the rod being offset of center of the choke plates it is expected for them to be forced open to some extent by the flow of air into the throats...value of how much is dependent on the amount of pedal being applied.

Quote:
The part that leaves me wondering is why is the carb flooding... the choke plates remain closed until I touch the throttle, I only touch the throttle because the engine is struggling so bad I am afraid to foul my plugs because of the excess fuel...
While the choke plates are closed and thus the throttle plate is resting partially open by reaction to the position of the choke plate position, the intake manifold pressure (depression) is able to travel up through the bore and venturi to the underside of the choke plate, this causes excess fuel to be drawn from the boost venturi.... its a starting feature that will never end until the plates are drawn open via the Choke Pull-off, once the choke plates are drawn open this depression drops to the next more restricting location, below the throttle plate.

This 'Pull-off' is a preset choke plate opening caused by manifold vacuum signal reaching a diaphragm and it is unrelated to the other extent of the function of the choke stystem.... heating (expansion) of the bimetal spring.

The auto 'Pull-off' relies on this vacuum signal diaphragm as well as an "O" ring, is this functioning?

Quote:
Thanks Terry, any adjustments you suggest I will perform tonight, yesterday I cleaned my air filter, the crankcase breather filter and fixed a problem with the power door locks I installed on the Jeep, I did not touch the carb yet, wanted to give you more information before starting adjustments.
Is electric current reaching the Bi-metal spring cup?

Earlier, I recommended that you adjust the spring tension via turning the cup.
Counterclockwise increases spring compression and therefore the amount of time (heat expansion) necessary to open the plates, clockwise rotation causes the opposite.

In order to rule out a spring malfunction I suggest you loosen the three retaining ring screws and rotate the cup an ample amount in both directions to assure that the spring is whole and that the 'eyelet' is capturing the pin inside the choke assembly. Once removed and reinstalled, missing the 'eyelet' is simplier than not... just a thought as to what maybe the cause.

Since your plans include a possible change to manual pull-off and once you see that the rotation of this bi-metal cup causes the plates to open as well as close them, and, the adjustment fails to bring the choke system into working order (for whatever reason), I suggest that you rotate and lock down the cup in the full open position... clockwise.

Then if the over rich condition continues, a look to the floats is in order and a 'How to' diagram will be provided.
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Unread 11-28-2011, 11:26 AM   #10
Fernando
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Quote:
While the choke plates are closed and thus the throttle plate is resting partially open by reaction to the position of the choke plate position, the intake manifold pressure (depression) is able to travel up through the bore and venturi to the underside of the choke plate, this causes excess fuel to be drawn from the boost venturi.... its a starting feature that will never end until the plates are drawn open via the Choke Pull-off, once the choke plates are drawn open this depression drops to the next more restricting location, below the throttle plate.

This 'Pull-off' is a preset choke plate opening caused by manifold vacuum signal reaching a diaphragm and it is unrelated to the other extent of the function of the choke stystem.... heating (expansion) of the bimetal spring.

The auto 'Pull-off' relies on this vacuum signal diaphragm as well as an "O" ring, is this functioning?
Where is this diaphragm on the Weber, so I may check this?

As I understand it, the choke causes a rich condition when it's closed, if I am suffering from excess fuel, and I turn the choke spring counterclockwise, it will take longer to open and will promote a richer condition, am I right?... this seems confusing to me, if I have excess fuel how would it fix it to prolong the rich state for longer?

After I touch the throttle the plates open almost to the full position, just by touching it. The choke plates engage some sort of fast idle mechanism which keeps the jeep under a slight acceleration, as soon as this fast idle device is disengaged the revs drop quite a bit, I think this may not be working as the Jeep starts with very low revs... could this be the cause as well?

Tonight I am adjusting the spring counterclockwise, what should I expect from this adjustment?

THANKS TERRY you're the man, I so wish you were my next door neighbor, I would learn so much from you. Thanks again

EDIT: I just thought of this.. is it normal for this fast idle mechanism to disengage that quickly? isn't this supposed to be a slow process of releasing until the throttle position is no longer affected? mine releases suddenly after the slightest touch to the gas pedal, I wish this would hold so I could drive away without having to wait for five minutes for the Jeep to warm up... if I drive away the fast idle is no longer working and my revs drop to around 400 rpm
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Originally Posted by JeepHammer
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Unread 11-28-2011, 12:09 PM   #11
mcmud
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Quote:
Originally Posted by Fernando View Post
Where is this diaphragm on the Weber, so I may check this?
It's in that tit looking housing that is pointing toward the firewall... Haha, I said 'tit' on the internet.
To test it you'd need to pull the carb, or, after cycling the pedal prior to the attempt to start to verify that 1.) the plate is indeed snapping fully closed and then, 2.) at the startup verify that the plate is being pulled open to that preset... if it is then it's indicating that both the 'O' ring and diaphragm are intact.

Quote:
As I understand it, the choke causes a rich condition when it's closed, if I am suffering from excess fuel, and I turn the choke spring counterclockwise, it will take longer to open and will promote a richer condition, am I right?... this seems confusing to me, if I have excess fuel how would it fix it to prolong the rich state for longer?
This is true, it would prolong the 'startup function'... rich. The suggestion was in attempt to see if the 'eyelet' and spring are intact and set as it should be. If for instance the eyelet isn't engaging the assembly pin or if the spring is in need of replacing (seldom if ever) this would cause the plates to malfunction.... the richness is yet to be corrected. See the statement below.

Quote:
After I touch the throttle the plates open almost to the full position, just by touching it. The choke plates engage some sort of fast idle mechanism which keeps the jeep under a slight acceleration, as soon as this fast idle device is disengaged the revs drop quite a bit, I think this may not be working as the Jeep starts with very low revs... could this be the cause as well?

Tonight I am adjusting the spring counterclockwise, what should I expect from this adjustment?
This is the one of the major concerns... this shouldn't be happening, check the bi-metal cup, in both directions of rotation.
While the engine is cold, if you find that this rotation will cause both opening as well as closing of the plates and the adjustment fails to end the issue, set it (the cup) fully open. It may cause you to need to restart the engine a time or two on a cold morning but at least its better than the issue you're now experiencing. FWIW I run two Webers without benefit of the choke.

Quote:
THANKS TERRY you're the man, I so wish you were my next door neighbor, I would learn so much from you. Thanks again
You're very welcome, Fernando. If we were neighbors you would either need to be a redneck or put up with my cluttering your neighborhood with jeep junk.

My friend, I'm as close as this keyboard.

Terry
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Unread 11-28-2011, 12:28 PM   #12
Fernando
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Very well Terry thanks for explaining all of this! there is no missing the tits haha excellent description!

I will adjust everything tonight and report back tomorrow.. will check the bi-metal spring, one last question

I noticed you can adjust the fast idle speed that engages while the choke plates are closed, what is your advice as per adjusting this screw? what RPM is good for startup? I have a feeling this screw may not be adjusted and I have very little acceleration on startup...

Thanks again!!
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Originally Posted by JeepHammer
I don't mind writing for Fernando because he reads, and re-reads EVERY WORD!... Good to write for someone that actually READS the answer, and takes time to UNDERSTAND what comes back for an answer!
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Unread 11-28-2011, 12:37 PM   #13
mcmud
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While the plates are completely closed back out that screw until it looses contact, then set the screw so it makes contact with the lever (cam) and make the first attempt at setting it at 3/8 to 1/2 turn inward, then start it, 1300 to 1700 rpm is most desirable... final adjustment is easily made while the engine is still cold, yet running.
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Unread 11-28-2011, 12:45 PM   #14
Fernando
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Quote:
Originally Posted by mcmud View Post
While the plates are completely closed back out that screw until it looses contact, then set the screw so it makes contact with the lever (cam) and make the first attempt at setting it at 3/8 to 1/2 turn inward, then start it, 1300 to 1700 rpm is most desirable... final adjustment is easily made while the engine is still cold, yet running.
Will do tonight and will report tomorrow!!
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Quote:
Originally Posted by JeepHammer
I don't mind writing for Fernando because he reads, and re-reads EVERY WORD!... Good to write for someone that actually READS the answer, and takes time to UNDERSTAND what comes back for an answer!
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Unread 11-28-2011, 10:33 PM   #15
Fernando
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Hi Terry and everyone else who is following this thread, I did my homework and I think I found the problem with the choke, Terry please correct me if I'm wrong...

I removed the choke, found out the preset vacuum mechanism which should open the choke plates just a little when the engine is cold is not working, there must be a vacuum leak or something but the diaphragm behind the carb is not strong enough to pull the piston and open the choke plates a bit... so what is happening is that very little air is coming through on startup and the Jeep runs super rich...

I have taken a video of the carb with the choke removed, you can clearly see the piston move a little bit when I start the engine, and then I had to manually push it with a screwdriver to complete its range of travel... I have left the choke fully open for now.

My question now, do I need to fix this diaphragm or can I just switch to manual choke? also if the diaphragm is not faulty, what could be the problem, what is the source of vacuum for this piston?

Terry thank you for all your explanations, when I removed the choke I was able to understand this part which I've never seen before because of what you explained to me, thanks a lot

If I'm wrong about anything please let me know...

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Quote:
Originally Posted by JeepHammer
I don't mind writing for Fernando because he reads, and re-reads EVERY WORD!... Good to write for someone that actually READS the answer, and takes time to UNDERSTAND what comes back for an answer!
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