TheSamba.com :: View topic - 71 Double Cab - New Owner and the newby-est question ever!

Mon Nov 09, 2009 7:26 pm

Tram wrote: The screw shouldn't contact the last step at all with the throttle plate fully closed and the choke fully open. The only function of that screw is to set fast idle speed; e.g., choke on. Once the choke is off and the "idle speed" screw is no longer contacting the last step, ....

That's wrong and erroneous advice. :shock:
The throttle valve stop screw should be adjusted in 1/4 turn after if contacts the the last position of the fast idle cam. That's assuming it has the Solex 34 PICT-3 carb that's used on the '71 dual port engine.
Jimmy- You need to get the service manual. It has the explicit instructions on carb adjustment and other things you will faced with. The info in that link is good and helpful. You still will need the manual.

Mon Nov 09, 2009 8:32 pm

Desertbusman wrote: Tram wrote: The screw shouldn't contact the last step at all with the throttle plate fully closed and the choke fully open. The only function of that screw is to set fast idle speed; e.g., choke on. Once the choke is off and the "idle speed" screw is no longer contacting the last step, ....

That's wrong and erroneous advice. :shock:
The throttle valve stop screw should be adjusted in 1/4 turn after if contacts the the last position of the fast idle cam. That's assuming it has the Solex 34 PICT-3 carb that's used on the '71 dual port engine.
Jimmy- You need to get the service manual. It has the explicit instructions on carb adjustment and other things you will faced with. The info in that link is good and helpful. You still will need the manual.

That's how we were trained by VW. Has something changed?

Edit: I went out to my "K" fuel systems manual to double- check your information. There is indeed a "4th Supplement" to the PICT-3 carburetor adjustment procedure dated 12.73 that I made the note "U.S. Spec Only" on years ago. I don't know that that was made SOP retroactively for all of them later, but it might have been. I don't recall any additional training on that carb. In any case, the 4th Supplement says to back that screw all the way out, then to where it's just touching the cam, then .25 of a turn in.

I've always followed the original procedure I noted on this where there's a small gap between the throttle lever screw with the choke off, and never had a problem. But then, I'm using a dwell tach and a sniffer when I set them, so the mix is right on. some of these carbs had an annoying tendency to stall or nearly stall very intermittently coming off highway speed, almost as if the throttle plate in the carb were "bouncing". There was also a service bulletin on some of these throttle plates sticking in the bore, so that might be why they made the change.

Mon Nov 09, 2009 9:33 pm

I just got back in from attempting carb tune as instructed in both the Bentley and the site posted above. All I succeeded in was making it run worse with very smokey exhaust and the occasional backfire. This is how it went down...

I re-timed the distributor to 28-30 degrees at 3000 RPMs and it fell at about 8 degrees at idle and the motor barely stayed running. So I shut 'er down and did the fast idle screw adjustment, then the volume screw (turned it in till it seated then out 2 3/4 turns. I started it up. The motor almost wouldnt stay running. I had to back it out another 1 1/4 turns to keep it going. The idle adjust screw (big one)did little or nothing no matter how much I turned it in or out. (Are you supposed to seat it then back it out as a starting point too?) As it sits now, it runs at about 900-1000 RPMs, smells rich, feels hot, has no guts, and stumbles on a test drive.

Hate to say it, but I think this motor is f**ked.

Mon Nov 09, 2009 10:01 pm

I love the 71 busses I have 2 myself and am dreaming of a doublecab so congrats.

My 71 deluxe's engine is set up much the same way 34 and 009 and it has taken quite a bit of tinkering to get it right. But the first step for me was to set the timing at idle and leave it alone, only change one thing at a time so you know what to fix later.

Then adjust the accelorator pump to max squirt. Then play with the air and fuel mixture screws to get what you want. I don't get to mired in specs as elevation and engine condition come into play. When I make an adjustment I listen and feel what the engine is doing. Is it laboring or missing? I'll turn an adustment screw in till the motor runs bad then out till in runs bad then find a place in the middle. Good Luck

Jon

Mon Nov 09, 2009 10:09 pm

I can get the thing to run better if I set the timing at idle but everything I have read about the 009 says you gotta do it at full advance. The thing that really concerns me is how smokey it is and the stumbling is just killing me.

Perhaps I will have to take it to someone and have them look at it. I dont have a compression tester, but I have a sinking feeling.... :? :(

Mon Nov 09, 2009 10:29 pm

jimmynotch wrote: I can get the thing to run better if I set the timing at idle but everything I have read about the 009 says you gotta do it at full advance. The thing that really concerns me is how smokey it is and the stumbling is just killing me.

Perhaps I will have to take it to someone and have them look at it. I dont have a compression tester, but I have a sinking feeling.... :? :(

Jimmy:

Calm down. One thing at a time.

Whenever you start adjusting things off the cuff, you wind up with a clusterfuck. I seriously doubt that you have a bad engine. It sounds to me like all the adjustments are out of whack. Remember: Before you start adjusting the fuel system, the prerequisites are valve adjustment being correct, charging system output being correct, and the ignition system being correct.

All three of those are building blocks that get you to the point of carburetor adjustment.

However, you're dealing with an 009 distributor, which puts you behind the 8 ball already, from the get go. The ignition system isn't stock! Plus, you're dealing with the exact problem these are notorious for: acceleration flat spot.

So, relax. Can you get the damn thing adjusted back to the way it was when you started? From now on, in these situations, ALWAYS find some way to leave yourself a clue so you can get back to where you started from. :wink:

Sounds to me like the timing's off, and you're running too rich. Check the oil, and make sure it's not fuel fouled. If that's good, then go back to the timing spec that you started with. Then, double- check the electric choke and the electronic cutoff jet, and make sure that the wires are hooked up, and they're working. In the case of the cutoff jet, make sure it's snug/ tight in its threaded bore- they're notorious for getting loose. Don't crank it down mega- tight; you'll strip the threads.

Mon Nov 09, 2009 10:45 pm

Tram wrote:
Jimmy:

Calm down. One thing at a time.

Whenever you start adjusting things off the cuff, you wind up with a clusterfuck. I seriously doubt that you have a bad engine. It sounds to me like all the adjustments are out of whack. Remember: Before you start adjusting the fuel system, the prerequisites are valve adjustment being correct, charging system output being correct, and the ignition system being correct.

All three of those are building blocks that get you to the point of carburetor adjustment.

However, you're dealing with an 009 distributor, which puts you behind the 8 ball already, from the get go. The ignition system isn't stock! Plus, you're dealing with the exact problem these are notorious for: acceleration flat spot.

So, relax. Can you get the damn thing adjusted back to the way it was when you started? From now on, in these situations, ALWAYS find some way to leave yourself a clue so you can get back to where you started from. :wink:

Sounds to me like the timing's off, and you're running too rich. Check the oil, and make sure it's not fuel fouled. If that's good, then go back to the timing spec that you started with. Then, double- check the electric choke and the electronic cutoff jet, and make sure that the wires are hooked up, and they're working. In the case of the cutoff jet, make sure it's snug/ tight in its threaded bore- they're notorious for getting loose. Don't crank it down mega- tight; you'll strip the threads.

Well I can get it to where it was but that was also waaaay off I think. As far as timing, the 009 is at where everyone says its supposed to be (except Bently :roll: The Bently say its supposed to be at 5* ATDC and its at like 8-10 BTDC ). I put it at where Bentley says and its ok as long as the carb is adjusted funky. So its all weird.

I am just at that frustration point, not all stressed out. The only thing that really bugs me is I cant tell if the smoke is from running rich or from burning oil. Kate actually came out of the house because she could smell it.

Mon Nov 09, 2009 10:53 pm

jimmynotch wrote: Tram wrote:
Jimmy:

Calm down. One thing at a time.

Whenever you start adjusting things off the cuff, you wind up with a clusterfuck. I seriously doubt that you have a bad engine. It sounds to me like all the adjustments are out of whack. Remember: Before you start adjusting the fuel system, the prerequisites are valve adjustment being correct, charging system output being correct, and the ignition system being correct.

All three of those are building blocks that get you to the point of carburetor adjustment.

However, you're dealing with an 009 distributor, which puts you behind the 8 ball already, from the get go. The ignition system isn't stock! Plus, you're dealing with the exact problem these are notorious for: acceleration flat spot.

So, relax. Can you get the damn thing adjusted back to the way it was when you started? From now on, in these situations, ALWAYS find some way to leave yourself a clue so you can get back to where you started from. :wink:

Sounds to me like the timing's off, and you're running too rich. Check the oil, and make sure it's not fuel fouled. If that's good, then go back to the timing spec that you started with. Then, double- check the electric choke and the electronic cutoff jet, and make sure that the wires are hooked up, and they're working. In the case of the cutoff jet, make sure it's snug/ tight in its threaded bore- they're notorious for getting loose. Don't crank it down mega- tight; you'll strip the threads.

Well I can get it to where it was but that was also waaaay off I think. As far as timing, the 009 is at where everyone says its supposed to be (except Bently :roll: The Bently say its supposed to be at 5* ATDC and its at like 8-10 BTDC ). I put it at where Bentley says and its ok as long as the carb is adjusted funky. So its all weird.

I am just at that frustration point, not all stressed out. The only thing that really bugs me is I cant tell if the smoke is from running rich or from burning oil. Kate actually came out of the house because she could smell it.

Bentley timing doesn't apply to the 009, because the 009 was never factory approved for this application.

Use this procedure for the carb:

Mon Nov 09, 2009 11:09 pm

I followed the Bently exatly. I still think it did better with the timing more around 5ATD to 0* but whatever. I will try a carb rebuild this week when I actually have time. For now, I am going to try to get it back to where it was minus the super high idle.

BTW, is there a starting point for the idle ajdust screw? As in, do I want to seat it then back it out 2 1/2 turns or something? Where would I call a starting point with it?

Mon Nov 09, 2009 11:12 pm

Jimmy - the factory distributor (which you refer to in the book and you do not have) has three advance mechanisms. At idle the retard mechanism pull it back to 5 degrees after top dead center. When you step on the gas the advance mechanism and the centrifigual mechanism advance it immediately to a BTDC position depending upon RPM and load. Trust me. I had a 1971 Deluxe for 350,000 miles and know how to tune a stock one or 009 because I had one of those for awhile. Just set the timing to 30 degrees BTDC at 3500 RPM. Just rev the engine slowly until it stops advancing and hold it there until you get the dist set to 30 degree BTDC. When it returns to idle it should be about 10 degrees BTDC or thereabouts (say (7 to 12 degrees BTDC).

As for your carb. Please take some photos of the big black thing on the back and how the hoses are routed to it. We need to see what it is and why it is there.

As for the smoke. If your float level is off that will really make it black smoke. The most common problem with carbs of that era, including replacements, is that factories used the cheapest floats around which are the hard foam ones. They slowly soak up gasoline, get heavier and start sinking. When that happens the fuel level rises in the carb and it starts to run really rich. You may need to rebuild the carb to see if it has that problem.

Mon Nov 09, 2009 11:16 pm

jimmynotch wrote:
Hate to say it, but I think this motor is f**ked.

Yep, it's probably shot. I'll be right up there to take it off your hands :wink: .
I think I'd start by doing a nice rebuild on the carb. $10 for a kit and you have the instructions. Do a super, super cleaning job on it, in all the passages. If you were nearby you could try one of my extra good working spare carbs. Maybe the smoke is it running real overly rich. The stumble might be because it needs more squirt from the accelerator pump. The book tells how to test the squirt but you can try a trial and error type of adjustment. I'd still time it at max advance but maybe down to 28 degrees might help. Bentley timing method does not apply to an 009. The Bentley proceedure is the way to adjust the carb. And they do adjust. If not they are having a problem.
My bug has the 34 PICT-3 and 009 with a Pertronix ignitor and it's at 29 or 30 degrees. Real quick and easy to adjust the carb. But you have points so that's adding to your complexity on getting the ignition wonderful. My bus has the 009 with Pertronix and then Baby Webers. The carbs were real difficult to get setup.
With the timing light see if the advance is smooth going up thru the RPM range. You don't drive it at idle that's why advance at speed is the important one. Quite a few of us are completely happy with our 009's. Simple, easy to tune, less mechanism and connections to mess up.

Mon Nov 09, 2009 11:18 pm

jimmynotch wrote: I followed the Bently exatly. I still think it did better with the timing more around 5ATD to 0* but whatever. I will try a carb rebuild this week when I actually have time. For now, I am going to try to get it back to where it was minus the super high idle.

BTW, is there a starting point for the idle ajdust screw? As in, do I want to seat it then back it out 2 1/2 turns or something? Where would I call a starting point with it?

I usually use 2- 2,5 turns as a starting point when I rebuild one. Other than that, you really shouldn't need a starting point. Just do what the procedure says, exactly. Don't try to outhink anything. The only starting point is the 2,5 turns on the volume screw, then adjust the bypass (idle) screw in to lower RPMs, out to increase them, until you get to the specified RPM. Then proceed from there with the fine tuning.

Mon Nov 09, 2009 11:26 pm

i have a newly rebuilt dist #113905205m that i bought off of here that you can buy for the same price i got it for if someone knows if it will work on your engine. supposed to be for a 1500-1600 engine

Tue Nov 10, 2009 12:33 am

Tram wrote:
I usually use 2- 2,5 turns as a starting point when I rebuild one. Other than that, you really shouldn't need a starting point. Just do what the procedure says, exactly. Don't try to outhink anything. The only starting point is the 2,5 turns on the volume screw, then adjust the bypass (idle) screw in to lower RPMs, out to increase them, until you get to the specified RPM. Then proceed from there with the fine tuning.

See thats what I did - exactly. But the idle adjust screw aint doing anything. The only thing making a difference is the volume screw, and at this point its around 4 turns out :shock: which is about where it was before I started all this crap. I think the PO had the same issue I am having 'cause I end up right back where I started. Whatever. I will save it for tomorrow. I have an ice cream headache now. :roll:

Tue Nov 10, 2009 12:38 am

jimmynotch wrote: Tram wrote:
I usually use 2- 2,5 turns as a starting point when I rebuild one. Other than that, you really shouldn't need a starting point. Just do what the procedure says, exactly. Don't try to outhink anything. The only starting point is the 2,5 turns on the volume screw, then adjust the bypass (idle) screw in to lower RPMs, out to increase them, until you get to the specified RPM. Then proceed from there with the fine tuning.

See thats what I did - exactly. But the idle adjust screw aint doing anything. The only thing making a difference is the volume screw, and at this point its around 4 turns out :shock: which is about where it was before I started all this crap. I think the PO had the same issue I am having 'cause I end up right back where I started. Whatever. I will save it for tomorrow. I have an ice cream headache now. :roll:

I think I'd look for a vacuum leak, just for fun.

Tue Nov 10, 2009 12:55 am

Well just now I sprayed carb cleaner all over and at the union between carb and manifold the RPMs go way up. Go figure. so I guess I pull the carb and replace the gasket.... tomorrow.

Must....

put....

tools...

down.

Tue Nov 10, 2009 1:08 am

jimmynotch wrote: Well just now I sprayed carb cleaner all over and at the union between carb and manifold the RPMs go way up. Go figure. so I guess I pull the carb and replace the gasket.... tomorrow.

Must....

put....

tools...

down.

Look really closely at where the brake booster line hooks to the manifold as well. :wink: Tomorrow, in the daylight...

Tue Nov 10, 2009 3:59 pm

Wellllll.... I replaced the gasket at the cab/manifold union. Helped things a little. I am still looking for an intake leak somewhere, but that is not the big issue. The big issue is #1 clyinder is not firing and is looking to be bad. When I pull the plug wires on at a time, the wire for # 1 does nothing... essentially I am running on three jugs. I haven't had the chance to do a compression test yet, but judging by the light colored smoke at the tailpipe, I'd say this is a tired motor. I am gonna look at valves and plugs one more time, check for intake leaks at the end castings and such, but I am losing my optimism. Sucks too because I am really needing a work truck and I was hyped on this DC. It will be a long while till I can afford a rebuild if thats what the verdict is.

Tue Nov 10, 2009 4:09 pm

Jimmy - you may have a bad pug, bad wire, distributor cap with a carbon track etc. Double check the those items and the valve adjustments on #1. Run a compression test on #1. You can buy a compression tester for about $10 at Harbor Freight.

If you were telling me that there was a loud knock or exhaust I might think #1 had a mechanical problem but you haven't said that so we are thinking it is an ignition spark issue on the cylinder or a mis-adjusted valve.

Tue Nov 10, 2009 4:20 pm

SGKent wrote: Jimmy - you may have a bad pug, bad wire, distributor cap with a carbon track etc. Double check the those items and the valve adjustments on #1. Run a compression test on #1. You can buy a compression tester for about $10 at Harbor Freight.

If you were telling me that there was a loud knock or exhaust I might think #1 had a mechanical problem but you haven't said that so we are thinking it is an ignition spark issue on the cylinder or a mis-adjusted valve.

The cap is brand new with new rotor. I will check out the wire too.

I am waiting now for the damn thing to cool down so I can address the valve and plug issue. As for a compression tester, I have that on the list of stuff to get at HF this evening.

What else would cause white-ish smoke?