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Have you been driving the car or just out from the winter?  Was the flat spot there before, last year?  

If yes to out from winter and no to second question, would say it was just dirty jets. 

 

 

No, I have been adjusting the carbs this year to get it running better. The carbs have been rebuilt. I’m thinking the accelerator pumps might have something to do with the pause(flat spot)? Not sure?

First, check your ignition timing.  It should be 30 - 32 degrees advance at 3000 rpm.

Do a road test to see if the hesitation is still there.

Second, adjust your mixture screws.  Run each one in until the engine begins to stumble, then back it out 1/4 - 1/2 turn til the engine smooths out.

Do a road test to see if the hesitation is still there.

Three, for whatever carbs you have, research how to adjust the accelerator pumps and start by turning each one in 1/2 turn at a time with a road test in between.  If you go more than 2 - 2-1/2 turns each with no improvement, then there's something else going on.

When they were rebuilt, did the rebuilder install different/larger venturiis?  

First, check your ignition timing.  It should be 30 - 32 degrees advance at 3000 rpm.

Do a road test to see if the hesitation is still there.

Second, adjust your mixture screws.  Run each one in until the engine begins to stumble, then back it out 1/4 - 1/2 turn til the engine smooths out.

Do a road test to see if the hesitation is still there.

Three, for whatever carbs you have, research how to adjust the accelerator pumps and start by turning each one in 1/2 turn at a time with a road test in between.  If you go more than 2 - 2-1/2 turns each with no improvement, then there's something else going on.

When they were rebuilt, did the rebuilder install different/larger venturiis?  

I’ve done the first two things you have mentioned. I will adjust the accelerator pumps like you suggested. I rebuilt the carbs myself. I believe the venturiis are stock. 

 

I solved that problem with an SVDA distributor. 009s suck, and they suck even more today than they ever did with the lack of precision and quality control from Asian sources.

However, if all was good and you rebuilt the carbs and NOW there's a problem, obviously it's the carb adjustments.

I ask again, every single time and get crickets: Solexes need 1.5 pounds of fuel pressure. What is your fuel pressure? If you don't know, you need to find out. Solex float valves can't handle more than 1.5 pounds. Truth.

Another thing to re-check is the float level in the bowl.  Those Solexes tend to be fussy about float level and yours might both be a tad low.  Worth re-checking, since it's easy to do.

But, even easier, is adjusting the accelerator squirt and you're already on to that, so try that first (as you suspected in the first place!)  Just go into this with a nice, "Zen" attitude - And have a beer ready for a successful conclusion.   

Last edited by Gordon Nichols
@DannyP posted:

I solved that problem with an SVDA distributor. 009s suck, and they suck even more today than they ever did with the lack of precision and quality control from Asian sources.

However, if all was good and you rebuilt the carbs and NOW there's a problem, obviously it's the carb adjustments.

I ask again, every single time and get crickets: Solexes need 1.5 pounds of fuel pressure. What is your fuel pressure? If you don't know, you need to find out. Solex float valves can't handle more than 1.5 pounds. Truth.

I believe my fuel pressure is 1.5psi at least last time I checked. It idles perfect at 1100rpm when all warmed up. It accelerates well, nice and smooth all the way to WOT. So spark plugs look good. Timing at 30 degrees. Spark plugs, wires, cap are all replaced last year. 

Another thing to re-check is the float level in the bowl.  Those Solexes tend to be fussy about float level and yours might both be a tad low.  Worth re-checking, since it's easy to do.

But, even easier, is adjusting the accelerator squirt and you're already on to that, so try that first (as you suspected in the first place!)  Just go into this with a nice, "Zen" attitude - And have a beer ready for a successful conclusion.   

How do you check float level on a Solex carb? I’m definitely going to try adjusting the accelerator pumps on the carbs

As Danny said .009 are notorius for flat spots on acceleration.  Adjusting accel pump and bigger jets were a fix.

The 009 distributor sometimes causes an acceleration "flat spot" (hesitation, stumbling, the Dreaded Bog!), as it does not have the vacuum advance adjustment of the original distributor. These can usually be overcome by ensuring that the accelerator pump is adjusted for it's maximum stroke, and installing a richer main jet in the carburetor (one size up should do it).

These 009 distributors were (and still are) sold by the ton. Early VW engines (pre-71′) had no problem, but the smog engines when equipped with the 009/010 distributors had a pronounced and annoying “flat spot”. A “flat spot” is a hesitation just off idle, and can range from being almost unnoticeable to getting broad-sided or rear-ended by approaching cars! (Many 009/34 equipped owners mistake this …

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