TheSamba.com :: View topic

Sat May 06, 2017 5:47 pm

Hey guys. MYbe I'll get more help over here. Not much traffic in the engine forum.

Some of you are familiar with my car but I'm trying to get it tuned up for some summer cruising.

Deets: new 1641. Broken in and maybe a few hours on it now. Tried to get it running last year then put it up for the winter.

So, valves at .006 per the builder. Timing set with a light. 6 bdc at idle 31 bdc at 1800/2000 rpm. New bocar 34 pict 3. I've gone through VW resource and set the idle and throttle set up as per the instructions. The problem is it's loading up at idle. When sitting at a stop light I have to keep a little throttle on it keep from dying. Fires up nice but like I said is loading up to the point that it dies if I just let it sit and idle.

Ideas? Sounds like I need to go down a number or two on the idle circuit jets.

Thanks gents.
Dustin.

Sat May 06, 2017 6:34 pm

How does it idle when you first start it, and after warming up a bit ?

Sat May 06, 2017 6:56 pm

What distributor is on the car.? Just curious , 31` is the most you want to go anyway .
I would check for a vacuum leak around the intake manifolds. Meaning its sucking in to much air per fuel ratio at idle . Are there any other reactions like popping out the carb ,sputtering or backfiring ?

Sat May 06, 2017 9:51 pm

Vacuum advance. To be honest not sure if it's single or dual advance. Need to look inside I guess.

On cold startup it doesn't want to keep itself at a high idle like the choke should even though the choke is closed. Loads up and dies if I don't idle it up by hand or foot feed.

I have checked all mounting surfaces and bolts etc to make sure of no vacuum leaks. It did sit all winter so it could be a gasket or O ring somewhere.

Lots of black soot on the chrome tips so that tells me it's rich. It will cough through the carb right off of idle to quick throttle up. But I can bring it up slow and clear it out and then runs smooth. Comes back to a good idle for 10/15 seconds then starts loading up again and dropping the idle and will die if I don't clear it it out or bring the idle up.

Pic just because.

Sun May 07, 2017 7:08 am

All your symptoms pointed to " carb icing,no pre-heat and crappy paper air filter combined with .009 dizzy vs PICT 34 carb"
But after seeing your pic,this eliminates all of that theory,looks pretty tight from here, and it does appear you have the vacuum inlet on the manifold plugged..
So..lets look at the ignition,have you checked the points gap and dwell angle?
tiny dab of grease ahead of the rubbing block,dipstick drop of oil under the rotor on the felt etc.
If the car was running fine before you stored it, I'd maybe suspect something there,IE points closed for months and slight pit..
Who knows,
-Matt

Sun May 07, 2017 7:36 am

Thanks for that. I'll look under the cap tomorrow when I get by the shop.

It's never really ran "good". I've been fighting the off idle stumble since I got it fired up.

I've been reading through VW resource article. What it doesn't jump out and say is which way with the screws will lean it out. I.E., in is richer, out is leaner or vise versa?

Thanks

Sun May 07, 2017 7:55 am

Assuming everything is sound with your ignition system, Then move to the carb settings, Is this a brand new out of the box carburetor? if so, it's a good idea to tear them down and clean everything,some people have had nasty findings in their brand new setups..could be as simple as blockage some where..
The mixture screw on most carbs generally enriches the mixture when being turned out,essentially letting in more fuel..so if your more than 2.5 out i'd say you're running rich..
If your plugs are fouled from all the mucking around,replace them
-Good luck

Sun May 07, 2017 11:41 am

Thanks for the help Fes. I'll mess with it tomorrow and report back. I'll pull a plug and see what it looks like. Yes it's a new carb out of the box.

Sun May 07, 2017 9:11 pm

motorhead364 wrote: Lots of black soot on the chrome tips so that tells me it's rich. Tail pipes aren't a good indicator of where the air/fuel mixture is at. Checking the spark plugs is a better way to tell if you're running too rich or too lean. Your spark plugs should look like this ↓ if the air/fuel mixture is set correctly.

Also, don't be afraid to increase fuel flow in the idle circuit by turning the carb's volume screw (the smaller one) out further than the 2 1/2 turns counterclockwise that's always recommended. Slowly keep turning until you reach the fastest idle speed. Play around with the larger bypass screw as well. Getting a good idle is a balancing act between these two adjustments. And make sure that the throttle arm on the carb is properly set and do NOT use this adjustment to regulate the idle speed.

It looks like you probably have an aftermarket SVDA distributor...essentially an '034' clone. The quality on these isn't the best but it'll do. Certainly better than an '009' for use with a 34-3 carb.

motorhead364 wrote: Sounds like I need to go down a number or two on the idle circuit jets. Don't start messing with the jets until you get a good read on your current mixture and you're positive all other settings (points gap, ignition timing, spark plug gap, valve clearance) are spot on. What you describe as 'loading up' may actually be insufficient fuel flow thru the idle circuit, so dropping the idle jet 2 sizes (that's a lot) may make matters even worse. For reference, I run a 135 main & 65 idle jet in a German Solex 34 PICT-3 on the bone-stock 1600 in my Beetle. This is at sea level...significant elevation increases will require leaner jetting.

BTW...I know you said that you checked, but this idle problem sounds like a classic symptom of a vacuum leak.

Mon May 08, 2017 6:07 am

Great info. Thank you. I will recheck everything for a leak, pull a plug or two and see where they are at.

Our elevation here is 3500 feet. we have to jet down our motorcycles and race cars etc. and jet up to go to Dallas which is 300 feet.

Thanks again.

Thu May 11, 2017 12:54 pm

Looks a little fat to me :shock:

Re did the VW resource idle setting procedure. Fires up and idles ok but it has the dreaded stumble. I can kill i by opening the throttle about halfway and keeping it there. Or with a quick snap of the throttle it just hesitates and goes back to idle. I can feather it up and "clear it out".

Waiting for a vid to upload the. I'll post that.

Thu May 11, 2017 1:41 pm

http://vid249.photobucket.com/albums/gg209/bantam4...zpivxh.mp4

Thu May 11, 2017 3:27 pm

Dang ,that is way to rich. Another guess is that the coil or condenser is getting weak and not sparking hot enough. I would do a spark color test next and also do a Ohm reading on the coil.

Some Info here:

https://www.thesamba.com/vw/forum/viewtopic.php?t=573839&highlight=test+coil

Thu May 11, 2017 3:33 pm

Quote: Looks a little fat to me Shocked

LOL, just a little. :)

Thu May 11, 2017 3:52 pm

motorhead364 wrote: Looks a little fat to me Yeah, just a little...

Do all the plugs look like that, or just that one? If it's just one, it could be caused by a weak, or non-existent, spark in that particular cylinder. Test to make sure that you're getting a proper spark at the plug.

If spark is good at all plugs, and they're all soot-black like that one (even after driving around for a while) then you've definitely got a fuel delivery problem. Check the fuel level in the float bowl by removing the carb's top after idling for a minute or two, then shutting down. The fuel level should be about 3/4" from the top of the float bowl with the float in place. If it's too high, the vacuum will suck additional gas into the carb's throat and result in an overly-rich mixture. You lower the level by adding a washer(s) under the fuel inlet valve in the carb's top. Also check your fuel pressure. Too much pressure can force more fuel past the inlet valve than the carb can handle. You only need 2-3 PSI at most.

The cause of a stumble like that is usually an accelerator pump that's not adjusted properly. Looking into the carb again, you should see a steady stream of fuel start to squirt from the pump's brass discharge nozzle the instant you start to open the throttle. Also, the stream of fuel should be directed toward the edge of the throttle plate so it goes right into the manifold as soon as the throttle starts to open. The nozzle can be gently bent to aim the discharge. The volume of gas put out by the accelerator pump can be adjusted on the right side of the carb. Here's the procedure: http://www.vw-resource.com/accelerator_pump.html#adjust
In the event that your fuel level is too high and your carb's already sucking in additional gas, it could be flooding out and stumbling with the addition of even more fuel from the accelerator pump when you crack open the throttle. Check the fuel level in the float bowl as described above.

Thu May 11, 2017 4:10 pm

^bump... at the point where your engine sputters, is where the plug is turning black. That means that at as you add air, the richness increases. It sounds like its flooding a bit. This was happening to me to a degree, and I counter intuitively dialed back the accelerator pump so it wouldn't squirt so much gas in there as I pushed the pedal. It got rid of much of that problem.

just a quick adjustment idea to narrow things down

DQ

Thu May 11, 2017 4:36 pm

Awesome info. Thanks guys.

All Plugs look like that, accel pump is adjusted correctly. That was one of the first things I did.

Carb, dizzy, fuel pump, coil and plugs are all brand new. I did think about pulling back a bit on the accel pump. It's shooting a nice big stream when I hit the throttle. No air leaks any where.

Idle jet on the side of the carb says 559.

I will check float level and pump psi tomorrow.

Thu May 11, 2017 5:02 pm

Quote: Carb, dizzy, fuel pump, coil and plugs are all brand new
new does not always equal good. fuel level in carb can be wrong, fuel pressure is often off on new pumps...
If you dont verify, its still an unknown. :cry:

Thu May 11, 2017 6:02 pm

motorhead364 wrote: I will check float level and pump psi tomorrow. Also check to see that the main jet in the bottom of the float bowl is screwed in tight. If you happen to have a jet gauge, you should also verify that the size is #127.5. Seems like the idle (pilot) jet is correct at #55, but you can verify that too with a gauge.
While you have the top off the carb, check the operation of the fuel inlet valve. Verify that it's also tight and that it has at least one copper gasket under it. While blowing into the inlet line, push in on the valve's pin. This should close off the inlet completely. If you can still force some air thru with the pin pushed in, replace the valve. A faulty/loose inlet valve can result in too much fuel in the float bowl.
One last thing while you have the carb opened up. Check that no fuel has leaked into the float thru a pinhole. This will also lead to excess fuel in the bowl.
I know that the carb is brand new, but you never know...

Thu May 11, 2017 9:07 pm

Yea I'm starting to see that even though it's all new doesn't mean good. I've seen a few people say they've had to disassemble and clean new bocars. I knew there would be some setup with a new carb so I'm not mad. Just want to get it running right.

I do have a jet gauge set so I'll check them out tomorrow or Saturday along with float level etc.

I'll report back.

Thanks again guys.