Spits and Sputters from Dual Solex 40PHH's

['76mintgrün'02]

16 hours ago, Dudeland said:

Why the zip tie on the dizzy? 

 

Probably because the clips that hold the cap on are made of soft steel and people have had problems with them getting deformed and letting the cap come off. 

 

I'm guessing the Zip-tie is a Clip-tie.

 

Tom

[TobyB]

...late to the party...

 

AFR is a good question.  In the old days we'd have

you playing with the transition ('idle') jets-

now, we harangue you into a wideband meter, because it

saves both time and money, ultimately.

And will get you more power.

 

Big question- you say it starts spitting.  From all 4?  1?  2? 

Air leaks don't tend to be distributed- usually only one bore

gets the problem unless it's bore wear- and then you just tune

around it with different jetting.  Float issues tend to be

2 bores.  

Suggestion- get a cheap camera, run without the air cleaning system,

and get it to do it on video to see if you can tell which carb(s) bore(s) are doing it.

 

I'd say it was ignition, too, but your problem's in a classic carb spot and

NOT in a classic ignition spot.

 

t

Weber, not so lex...

[2002#3]

Thanks, everyone, for the continuing comments.  Over the next 2 days I will address all the aforementioned potential problem items and report.  ...and Toby, you ain't no Late Man.

Larry

[2002#3]

Hans, Zinz, Jam, Slavs, Dude, Jgerock, Mintgrun, and Toby,

 

I kept the air filters off to make the months of carb and timing tweaks and adjustments easier.  Today, addition of the sponge air filters reduced the spitting 80-90%.  Much better.  I never thought that amount of restriction would make a difference.  Still spits; however, much less occasionally.

 

Here are my responses and observations re: your enquiries, questions, and suggestion re: spitting at a constant 2,300 rpm or so.  THANK YOU for your help so far. 

1. Spitting reproducible without load?  yes
2. What is between the carbs and the intake?  gasket, plastic spacer, gasket.  Gaskets are homemade and the spacers were sanded smooth while resting on a glass surface.  PHOTO
3. Shaft wear?  not detectable in any plane
4. Idle jets?  57.5
5. AFR @ problem?  range, 15-18; mostly, 16-18; occassionally hangs at, 17-18. 
6. AFR routine?  idle, 12.6, or so; cruise, 14.6 or so; WOT, drops appropriatelyto 10.5
7. Zip tie?  to assure 123 clips stay secure
8. 123 rotor?  came with the 123; good condition
9. Venturi size?  40/32
10. Which barrels spit?  warming up, all (very obvious but only for 1-2 min); idle and at problem rpm, all (cannot really feel with hand; hard to tell b/c so subtle)  NOTE:  #1 is the most common suspect.
11. Advance curve?  the best of the 100 I have tried is attached.  PHOTOS
12. Problem occurs with air cleaners?  Yes but dramatically reduced.  My air filter can is for a 2002CS and needs to be modified to use in this car. PHOTO

[Jam3422]

Right, so it's going lean during transition.  Your idle jets are big, but I guess that's probably because you are running a 32 choke, rahter than the standard 34.  I'd try the next bigger jet.  Going from 52.5 to 53 made a pretty big difference for me.  You could also try the idle a little richer and see if that helps.  By cruise, do you mean >3k rpm under load?  Mine like to cruise at 12.5-13.5 depending on the jetting.  What are you using for main jets?

[Dudeland]

Where is the Vac advance plugged into?  Where I am headed with this is if the vac advance is not getting the correct signal you could be running as much as 50 degrees of advance.  I am not sure if this would explain spitting out the carbs.  I am not that knowledgeable. 

 

40 seems kinda high,  with my crank trigger I found a sweet spot around 36-38 degrees to total advance.  I am wondering if the dizzy is not indexed correctly. 

 

Just some early morning spitballing with my coffee.   This is an interesting one. 

 

[Hans]

2 hours ago, Dudeland said:

Where is the Vac advance plugged into?  Where I am headed with this is if the vac advance is not getting the correct signal you could be running as much as 50 degrees of advance.  I am not sure if this would explain spitting out the carbs.  I am not that knowledgeable. 

 

40 seems kinda high,  with my crank trigger I found a sweet spot around 36-38 degrees to total advance.  I am wondering if the dizzy is not indexed correctly. 

 

Just some early morning spitballing with my coffee.   This is an interesting one. 

 

Does the 123 have vacuum advance?

I agree, advance seems a bit extreme for today's fuels. The Scoob would approve though.

['76mintgrün'02]

8 minutes ago, Hans said:

Does the 123 have vacuum advance?

 

16 hours ago, 2002#3 said:

 

[Hans]

With all respect to your craftmanship, I'd be looking at that gasket arrangement. While each side of teh spacer might be flat and smooth - might - are they parallel? BTW, the DCOE gaskets fit on there. Assuming there are no clearance issues, you might try running with just a proper gasket to see what happens.

[Hans]

10 hours ago, '76mintgrün'02 said:

 

 

Learn something new every day.  So yes, where is OP getting vacuum?

[2002#3]

Update

 

1.  ordered a few different size idle jets

2. ordered "real" intake gaskets (The suggestion was 40 DCOE gaskets should work.)

3.  changed the max advance to 33; will play with maxes of 33-38

4.  will examine plastic spacers and measure for uniform thickness

5.  Vacuum?  What vacuum?  The 123 has a vacuum port but my intake and carbs do not.  Hmmm...  As I recall, plugging the 123 vacuum port does not make a difference in performance.  Hmmm...  Does something need to start sucking?  Help me here!

6.  I removed the carpet today.  Did not help with the carb issue.

 

Larry

 

 

[Hans]

Unless there is a clearance issue, I'd try mounting with just one new gasket and see what happens. 

[2002#3]

Hans,

...and omit the spacer and one gasket?  That should reduce the leakage options from 16 to 4.  Will try.  Do other dual carb setups have/need spacers?

Interesting:  I obtained this car for one reason - to get experience with carbs.  I'm gettin' it!

Thanks,

Larry

[Hans]

I think the spacers were for insulation. Webers seem to work fine without them on the same manifolds. i'd try it to see if that solves problem. 

[Jam3422]

Larry:

 

I suggest changing and assessing one variable at a time.  Confirming that you don't have leaks should probably be the first step.  The correct gaskets are available, and if you continue to use the spacers, use both gaskets for each spacer.  I wouldn't elimate the spacer unless you confirm they are causing a leak, and if they are, just get new ones.  If you do have a manifold leak, it should be relatively easy to find using your technique of spraying carb cleaner or something similar around potential offending areas.  Be sure to check the manifold/head interface carefully.

 

Once you have confirmed there are no leaks, before getting into swapping jets, you might try increasing the idle to the point you are going lean and getting the popping.  Then see if you can dial it out using the mixture screw.  It won't fix the problem, but it might narrow the issue to one carb barrel.