TheSamba.com :: View topic - Advice needed on carb and distributor setup!

Mon Jul 11, 2005 7:02 pm

My 1972 Regular Beetle 1600 is about to drive me nuts! It is equipped with the factory 34 pict carb and factory dual vac distributor. When I got the car it had a 009 and 30 PICT carb. The 009 and 30 pict carb had problems with wanting to buck and snort on takeoff. I had a good dual vac distributor and 34 pict carb so I rebuilt the 34 pict, checked the distributor out good and installed them. The car ran like a dream. Drive it about two weeks and you have to adjust the carb to get it to run right. I'm sick and tired of having to adjust the carb every couple of weeks. THe car will get to where it does not want to idle and when you take off it will hesitate as if it is not getting enough fuel. Let off the gas and it will feel as if it has more power. I have a good rebuildable Weber single barrel carb and many different varieties of distributors I can put on the car. Any suggestions as to what I can do to put and end to my idle and performance problems. Oh yes, it seems to get worse when it rains. The car has all new ignition components... coil, plugs, points, condensor, cap, rotor, wires. Any help pwould be nice! aaron

Mon Jul 11, 2005 7:39 pm

Welcome to the Samba Aaron!! Your in the right place!!

Make sure your heat risers are gettin hot, real hot. They may be clogged.!

There may be some crud or rust gettin through your fuel filter and gettin in the jets in the carb. How does the tank look inside??

Look for vacumn leaks in the intake manifold and carb.

Get a personal copy of the Bentley Manual for your year.

Keep comin back you'll need it!! :lol:

Tue Jul 12, 2005 2:14 am

Your distributor's vacuum advance mechanism is sticking. You need to do a complete teardown and cleanup of the whole distributor. It should be good for another 30 years after that.

Tue Jul 12, 2005 6:08 am

Ok, already checked the heat risers... they were hot as hell on both sides. Hot enough I could not hold them. When I installed the original distributor I totally disassembled it and cleaned and lubed everything. The distributor looked like a brand new one when I put it in the engine. Far as the fuel problem, that is a good possibility. The problem got really bad after I got some of what I thought was bad gas on my way home from school once a couple months ago. I fueled up and about 40 miles later the car quit on me. Went to the rear and found no fuel in the filter (external filter between pump and carb). Removed cover on fuel pump and that filter was slap full of what I would call silt and not rust. Cleaned it up and blew out the external filter as best I could and made it the remaining 250 miles home. I'm not real good when it comes to this VW carb. Is the 34 PICT that sensitive to contamination? I guess it may be a good idea to pull the carb and check everything out again. It's possible some of that stuff made it into the carb. Seems that it got worse after the fuel incident. Far as the fuel tank being rusty... I don't think so but it's possible. My car is a 72 that is all original. Even solid floor pans. The exterior has suface rust from the wornout original paint. I've ran this car every day since the day I got it. IT would seem that the 4,000 miles prior to getting the bad gas it would have acted up had the tank been rusty. I've checked the filters since and no silt in them. Do you guys think i'm better keeping the 34 PICT and dual distributor? Thank You and sorry so long. I want to get my baby running right again!

Tue Jul 12, 2005 7:25 am

What those guys above said + I would check the fuel pump withg a vacuum/mecanical fuel pressure gauge to see what kind of pressure I am getting.

Are you positive that the vacuum hoses are hooked up corretly on this thing?

From www.type2.com

Distributor Vacuum Hoses - Where Do They Go?
by Jim Thompson
--------------------------------------------------------------------------------

Over the years, many a 71-74 Beetle and 71 Bus with Dual Diaphragm Distributors have graced my doors and about half the time the vacuum lines are backwards. So here's the poop:

First, take a look at your Vacuum can. On the flat side of the can is a hose fitting - for the larger (4.5mm GREEN) hose. This is the RETARD side.

Second, on the cone (or rounded) side of the can is the smaller hose fitting. This uses a 3.5mm hose, usually black. This is the ADVANCE side.

Third, look at your 34PICT Carburetor. The fitting on the LEFT side of the carb is for the ADVANCE side of your Vaccum can. Connect appropriately.

Fourth, look at your 34PICT Carb again. On the rear (RIR) of the carb should be a fitting up towards, but not on the carburetor top. This push-on fitting is just slightly larger than then one on the side. This is for your RETARD side of your Vacuum can. Connect appropriately with the 4.5mm Green Hose.

Fifth, Any other fittings on your 34PICT Carb are for the infamous Throttle Positioner sometimes improperly called a "Decel Valve". The fitting for this jewel is an angled one right at the rear base of the carburetor. Connect the small vacuum hose to it to the Throttle Positioner Diaphragm Fitting. If your Throttle Positioner has two fittings (as original on 71 Buses, 71-74 Beetles), connect another length of 3.5mm vacuum hose from that to the Throttle Positioner Solenoid, usually located in the left side of the engine compartment. If you don't have the Throttle Positioner, cap off all the remaining fittings on your carburetor.

If you're running one of those new replacement H30/31PICT carbs, the procedure above is the same as they come with these fittings like their distant 34PICT cousins. Original 30PICT Series did not have the RETARD fitting, except for Beetle Auto-Suck Models - BUT - this fitting was for the Auto-Suck Solenoid, not the distributor because they were still single vacuum models (Actually, the Auto-Suck use a combined vacuum/mechanical distributor similar to the 76-78 Buses). Buses don't have these, right? So use this fitting for your RETARD side of the Dual Diaphragm Can.

Timing is usually 5 degrees AFTER Top Dead Center when using a Dual Diaphragm Distributor, give or take a degree or two - no two engine setups or running conditions are the same, so you''' have to fool with with of course. One other thing - Strobe Light at idle speed with the hoses CONNECTED. Sorry, no static timing with these, except to initially set the distributor at 0 TDC, start the engine, then strobiscopically time it after it warms up.

For those wanting to put a stock push-pull distributor back on their 71 Dual Port 1600 with a 34PICT (or other Bus with the same arrangement, here's the skinny on interchangeable distributors. All have the same Advance/Retard Curve specifications:

Vacuum: 2-5deg Adv @ 6.7 In. Hg, 11-13deg Ret @ 9.1 In. Hg
Centrifugal Advance: 6-12deg @ 1500rpm, 22-25deg @3800rpm

Tue Jul 12, 2005 7:53 am

I went out and looked at the car and the vacuum lines are connected properly. The Fuel pump is a new unit (was doing this before I replaced it). That is a very informative site that I have used before. I'm thinking that something has got to be in the carb itself. Guess I will pull it in the next day or so and check it out good. I may even play around with the timing some. I set the timing to 7 degrees per factory spec but that may need altering somewhat. I can adjust the carb per factory spec and it will run good for a few days then go back to running like crap. The engine in the car was rebuilt by Roy Rogers in Memphis less than 10,000 miles ago but when I bought the car it had been sitting close to 2 years with what the owner thought was a frozen engine. I got the car home and found that the starter was stuck on the flywheel. I got it free and have yet to have that happen again. I have put around 7,000 miles on the car and uses less than 1 quart of oil between oil changes. It does not seem to have the power it should either! I realize that a 1600 will be weak but if these thing's will move a bus then certainly it will move this Beetle a lot better than it does. The engine only seems to come alive at high RPM's. Also, the engine seems to run hotter than it should. I can run the car for about ten miles and when I get out and check the dipstick it will be so hot you cannot hold it. I've checked all the tin and all is in place, the thermostat seems to be working right and the engine seal is in good condition. I've yet to do a compression check... figuring that the engine was recently rebuilt it would be ok but i'm having second thoughts. I have a really good condition case that i'm thinking about starting to rebuild. Thanks all for the help. I love this site and have used it since I got my car. THis weekend I will be attending yet another VW show in Decatur, AL. Hope to see soem of you there. Aaron

Tue Jul 12, 2005 10:55 am

Ok, got out there with the car and did some checking. I feel like an idiot! The distributor vacuum advance was not working. Found that one of the screws was touching the point plate and preventing the distributor from advancing. The only advance it had was the centrifigal at high RPM's I would guess. Adjusted the timing to 5 degrees and the car runs 100% better although it still seems to be running to hot. Did not do the compression check yet but wondering if maybe the engine has weak compression causing it to run hotter than normal. Everything else is either new or OK. Thanks for the help guys!
Aaron

Tue Jul 12, 2005 11:42 am

Try adjusting the valves and then doing a compression test on it while it is still warm. The baywindow FAQs has a good way of doing that BTW.

Do the "oil squirt" part also.

Give us all of those numbers.