TheSamba.com :: View topic - 1973 bus

Wed Feb 10, 2010 12:21 pm

1700cc, Dual carb, 1973

I thought I'd put some pictures up because I'm stuck on
some problems... I have read the posts on adjusting carbs
such as:
http://www.ratwell.com/technical/DualCarbs.html

http://www.thesamba.com/vw/forum/viewtopic.php?t=173175

however, my problem is that there's a few things that aren't connected.

*The PO replaced the stock large air filter that connects both carbs
with two little air filters. Didn't take a picture of those though.

The car currently will start up, Sometimes if I give it gas a little pump
it will rev really high and then come down and stall. It will stall
while driving if I'm not constantly giving it gas. Like at a stop sign.

There's a little gas leak coming from near the accelerator
pump on the right carb.

From what I've read I probably have some sort of vacuum leak,
need to adjust the level of the floats, and other possible things
messing me up.

Here are the pictures: Let me know what you think, Thanks.

The photos can be found here... where you can zoom in:
http://picasaweb.google.com/circlethetree/1973VWBusEnginePhotos#

left side

Two hoses coming from the vacuum on distributor. One green, going to the left carb. One black that you see in the photo going no where.

Left Carb.

left carb

-Ryan

EDIT: So it's been several weeks since I posted this. Since then I've done a few things and it's idling solidly now. I got a lot of new hoses and replaced all the ones that were old. I recommend getting them as a package from the guy who offers a link to them below in this thread. It is decently priced.. Ratwell's site has the dimensions for the hoses if you want to get them yourself. Some of the hoses were so brittle they broke when bent. Also found a stock air filter housing assembly at a vw scrap yard. It felt great to get rid of those chrome things. Also replaced the wiring to all the solenoids and cleaned out all the solenoids. I'm very grateful for all the awesome diagrams/procedures by Colin. I recommend printing them out - and if you don't have a color printer, get some colored pencils and color them yourself - you'll learn a lot.

Wed Feb 10, 2010 12:34 pm

see that little gold colored can with in the photo of carb 2nd from bottom pic? that is an idle cutoff. it appears that it has no wire going to it. it needs 12v + going to it, switched from ignition. like from coil +. it will never stay idleing if that doesnt work. you can test it by hooking it to pos, and seeing if it clicks. check your bentley wiring diagram.

Wed Feb 10, 2010 12:37 pm

it's a mess, but you can recover. much of what you need is still there. you need the original air filter housing. whoever worked on the carbs before you was completely clueless on how they operate.

there are so many things wrong in the photos i barely know where to begin. it's odd the engine will run at all with there being no power to the idle solenoid and pilot jets. also the central idle circuit intake pipe is covered with a rubber cap, that cannot be, the left carb uses that pipe to suck in air supply for idle. what you need is colin kellog (amskeptic) to visit you for a day and sort it all out. maybe he can do a digital house call...

start here (thread below) and see what your setup should look like. and study the bentley section on dual carburetors.

http://www.thesamba.com/vw/forum/viewtopic.php?t=398662

Wed Feb 10, 2010 1:27 pm

These are the exact sort of responses I was looking for.

Any idea what the tube is in the center of the first photo
with a crimp in it? Is that crimp in the tube supposed to
be there?

Any idea what the mess of wires next to the battery was
once for? - Carbs?

Can I take an air filter housing off of a 1972 bus?
Or is it worth $100 to buy one from a 1973 bus?

Maybe I should start a different thread for these questions?

Thanks guys-
Ryan

Wed Feb 10, 2010 2:03 pm

keep this in one thread...
RyanPatrick wrote: Any idea what the tube is in the center of the first photowith a crimp in it?

Any idea what the mess of wires next to the battery was
once for? - Carbs?

the '73 air filter housing is different from the '72. we have used if you're in need of it.

the crimped tube is part of the air injection system which has been partly removed already. the wires are probably for the booster fan and might be part of the vacuum advance cutoff circuit. i didn't study that part of the photo closely. they have nothing to do with the carbs i don't think.

Thu Feb 11, 2010 6:22 pm

silverside61 wrote: see that little gold colored can with in the photo of carb 2nd from bottom pic? that is an idle cutoff. it appears that it has no wire going to it. it needs 12v + going to it, switched from ignition. like from coil +. it will never stay idleing if that doesnt work. you can test it by hooking it to pos, and seeing if it clicks. check your bentley wiring diagram.

So I ran a wire to this idle cutoff solenoid, and it didn't help with it idling at all. (It would click). I removed the cap that was covering the central air intake, and that didn't do anything for idling either.
The Central cut-off solenoid would click as well.
The other rectangular one, which I'm pretty sure is called the central fuel-enrichment, doesn't click when 12v positive is brought to it.

When I cover both of the carbs with my hands, the engine revs up really high...
Not sure why that is.

Something else I just did that I read on another post was to check for leaking connections with the manifold by spraying carb cleaner down at the base. It is getting dark outside so I can't see exactly where I'm spraying... but I sprayed some low and down there and after a few seconds (I'm back there keeping it going by giving it gas) there was some flames down there, also some flames came up through the carb.

Thu Feb 11, 2010 6:52 pm

you need a more thorough approach. the complete system needs to be present and all hoses, electrical connections, components etc. should be in place tested and working. then you can start to troubleshoot and tune.

Thu Feb 11, 2010 6:55 pm

I see where the flame is coming from down on the left carb. I didn't even see this tube with nothing attached to it. It is coming from the intake manifold towards the front. I'll have to check to see where this should go to.
Talk about a leak... :)

Thu Feb 11, 2010 7:01 pm

Sounds like you found one of your problems but I agree with Scott, get everything you can see hooked/wired/plumbed up properly first and see how it works after that.

Thu Feb 11, 2010 7:19 pm

Yeah... I agree. The problem is, I'm not sure I want to pay the hundred bucks for an original air filter quite yet. I want to be able to get it to drive without stalling out first. It should be able to do that without the large air filter, right? I need some confidence in this machine before I throw more money at it. I know they say I need a complete system, but the PO was able to drive it around without it stalling like this.
Yeah, that large hole down there was the reason it wasn't idling. (That brake booster sure can hide down there if you don't know what you're looking for.) I'll have to check tomorrow if it will still stall when I take it for a drive around the block. Here I have all the awesome diagrams and information by Colin printed out, but they can't serve me with this hacked-up system... Like my right carb is missing the right cut-off jet.

Thu Feb 11, 2010 7:34 pm

RyanPatrick wrote: The problem is, I'm not sure I want to pay the hundred bucks for an original air filter quite yet. I want to be able to get it to drive without stalling out first. It should be able to do that without the large air filter, right?

As everyone has already told you, you need a COMPLETE system in place before you attempt any sort of tuning, including the air filter assembly. I told you in the other post you started about your air filter problem that I had one if you were interested, but you haven't contacted me so I have to assume you're not. Half assed is not the way to approach this. You're either into it and gonna do it right and be rewarded with a well running machine, or you're not into in and you're gonna try and nickle and dime it together and end up selling it off disappointed and telling everyone you know what a piece of shit it was. Time spent making sure it's right is time well spent.

Thu Feb 11, 2010 7:51 pm

I'll pick up the air filter here in town...
You think I can get the elbows and most tubing at a parts store like NAPA?
How can I tell if the central fuel enrichment solenoid is functioning? Will it click with power?
Let you know how it goes once it's all connected up... the Right way. :)

Thu Feb 11, 2010 8:00 pm

Your best bet honestly on the dual carbs is to PM Amskeptic, he'll be able to walk you through everything you need to know. As for parts from NAPA--highly doubtful. These are old vehicles and it's just not economically feasible for parts stores to stock parts for them. You're gonna have to get comfortable with the idea of mail ordering sooner or later. Even if by some miracle you could get what you needed at a NAPA, the quality would be sketchy at best. Shop around and buy the best part you can afford. There are a lot of shitty low quality parts out there for our Buses, and doing the job twice because you wanted to save a couple bucks on the first go round just doesn't make any sense to me.

Thu Feb 11, 2010 8:20 pm

Don't expect that rectangular enrichment device on the outer side of the left carb to click, it may silently get warm after quite a few minutes but it'll never click. Odds are good the seals in it are petrified and it's permanently in warm mode anyways. Leave it disconnected for now and expect it to run a little crappy and quit occasionally for the first few minutes when it's cold on a cool day. Once you get all the other issues dialed in mess with it, but leave it alone for now.

Thu Feb 11, 2010 9:15 pm

RyanPatrick wrote: I'll pick up the air filter here in town...
You think I can get the elbows and most tubing at a parts store like NAPA?

most of the hoses in your pics look OK, as if they have been replaced not too long ago.

we have a kit:

http://www.germansupply.com/home/customer/product.php?productid=17911

the sizes of the hoses are all metric and not too likely to be found at NAPA. but you never know...

Fri Feb 12, 2010 8:19 pm

Found a guy with an air filter housing. He doesn't know if it is from a '73 or '74.
Anyone know how to tell the difference and if it will work for a '73 if it is from a '74? Or are they identical?

Fri Feb 12, 2010 8:52 pm

Post a picture , heres a picture of part of my 73!

I can remove mine and take some photos if you need them?

Fri Feb 12, 2010 8:55 pm

If it isn't too much trouble for you... thank you
I'd be great to see what one for a '73 looks like...

-Ryan

Sat Feb 13, 2010 9:11 am

the '73 and '74 plastic air filter housings are the same.

Sat Feb 13, 2010 11:10 am

Looks like the driver pulley for the smog pump has broken off the crank pulley; very common. Someone may suggest a work-around on that... unless you're in a state that requires your vehicle be inspected, including a 'visual'.

BTW there's a nice info piece on your bus's emissions control systems right here on the Samba http://www.thesamba.com/vw/archives/manuals/73emissions.php

Good luck solving the mysteries.