The canister is not your bogging problem. I would look at injector spray patterns, fuel delivery, excessive deposits behind the intake valves and/or worn valve guides or any other engine health issues. 

The carbon canister is a maintenance part. Back when my parents had their beetle and bus dealer serviced I recall that part being replaced on the beetle (71) at around the 60k service. 

Dennis
 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Ryan Perry
Sent: Friday, August 15, 2014 8:01 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: WTB: EVAP charcoal canister

Agree, wouldn't mind knowing what to look for with the canister. I have had an issue with off-idle bog since I bought my '84 with 1.9. Idle switch is good, vacuum lines seem good, think it could be a clogged charcoal canister that needs to be revved up before getting flow?

Ryan Perry

On Fri, Aug 15, 2014 at 4:38 AM, Michael Magnani <mfmagnani@sbcglobal.net>
wrote:

> I was just wondering.....  Is there any preventive maintenance or 
> inspections we should be doing to the EVAP system to avoid having problems?
> My 1990 2.1 WB runs fine and I'd like to keep it that way.
> Mike M
>
> Sent from my iPad
>
> > On Aug 14, 2014, at 17:10, Dennis Haynes <d23haynes57@HOTMAIL.COM>
> wrote:
> >
> > The new canister does still have a bottom vent, a large one. Just 
> > not
> through a hose tucked into the frame. Fuel vapor containment/recovery 
> systems have been with us since the late 60's. The purge valve on your 
> vanagon was vacuum operated and opened as the throttle opened. Later 
> vehicles even have an air pump to pressurize the system and failure to 
> hold pressure gives a fault code.
> >
> > Dennis
> >
> >
> > -----Original Message-----
> > From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On 
> > Behalf
> Of Neil N
> > Sent: Thursday, August 14, 2014 3:10 PM
> > To: vanagon@GERRY.VANAGON.COM
> > Subject: Re: WTB: EVAP charcoal canister
> >
> > Very helpful responses folks and thanks for the pmails.  I will 
> > inspect
> the vent hose from bottom of canister. It indeed vents to atmosphere. 
> I may also try removing the hose at canister inlet.
> >
> > Dennis: ill google up that part number. Much thanks. Is the lack of
> venting at new canister a potential problem in that there is no fail safe?
> (Then again, some vanagons already have EVAP "venting" in the form of 
> poor maintenance.  ;).  Ha ha. )
> >
> > The engine is running ok now but I'd like to address this issue soon.
> The forestry roads are tempting..... Given the noisy state parks I'm
> > encountering.     ;)
> >
> > Heat, engine load (long grade), small tank outlet not withstanding, 
> > my
> Jetta engine management operates the purge valve in a series of short 
> pulses at idle and possibly at other RPMs but if I'm not mistaken, the 
> stock WBX purge valve allows air to be constantly pulled soon after idle.
> Maybe there's subtle differences between the Mk 3 Jetta and vanagon 
> fuel tank and EVAP ?
> >
> > I don't recall seeing a purge valve on my vanagon while it was still 
> > in
> OEM air cooled form. I'll read my Bentley.
> >
> > Neil.
> >
> > On Thursday, August 14, 2014, Dennis Haynes 
> > <d23haynes57@hotmail.com>
> wrote:
> >
> > I believe the replacement number is 175-201-801-A. The new one does 
> > not
> use
> >> the hose connection on the bottom.
> >>
> >>
> >> Dennis
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> From: 'OlRivrRat'
> >> Sent: ‎Wednesday‎, ‎August‎ ‎13‎, ‎2014 ‎4‎:‎05‎ ‎PM
> >> To: Vanagon
> >>
> >>
> >>
> >>
> >>
> >>                Neil
> >>
> >>        I would start pulling hoses off the Canister to see if any 
> >> Disconnects make it run better ~ Especially check
> >>
> >> the BottomHose if yours still DeadEnds into the FrameRail as some 
> >> MudDobbingBug may have built a Nest in it ~
> >>
> >>
> >>              ORR ~ DeanB
> >>
> >>> On 13 Aug , 2014, at 1:33 PM, Neil N wrote:
> >>>
> >>> Hi folks.
> >>>
> >>> I am fairly certain that the Vanagon charcoal filter canister is NLA.
> >> This
> >>> would be for a 1981 gas Vanagon.
> >>>
> >>> I'm currently in Brookings OR and can travel a reasonable distance.
> >>> My
> >> bus
> >>> is running ok right now but if anyone had a known good canister 
> >>> they
> >> could
> >>> sell me or could suggest a source (wrecker, etc.) I might be 
> >>> interested
> >> in
> >>> it.
> >>>
> >>> I have not confirmed if the current canister at fault or if it's 
> >>> simply a clogged hose but I'm about 100% certain it is or will 
> >>> soon
> fail.
> >>>
> >>> Thanks,
> >>>
> >>> Neil.
> >>>
> >>>
> >>> On Wednesday, August 13, 2014, Neil N <musomuso@gmail.com 
> >>> <javascript:;>>
> >> wrote:
> >>>
> >>>> .......
> >>>>
> >>>> Very interesting to know more of the canister construction. Very
> >> helpful.
> >>>> I'll cut open the old 1981 vanagon high mile canister and post 
> >>>> pics. I
> >> have
> >>>> a Jetta canister I can install. It has a nearly identical exterior.
> >>>>
> >>>> Of note, the fuel pump doesn't make much if any noise right now 
> >>>> but has "always" gotten era all noisy on hot days, higher 
> >>>> altitude, workinengine harder.
> >>>>
> >>>> This is a Jetta engine in my vanagon but ever since I'd gotten it 
> >>>> to run reliably, it's always exhibited a tendency to run well, 
> >>>> or, feel like it had slightly less power and acceleration. I have 
> >>>> to wonder if this has
> >> been
> >>>> due to a failing charcoal c
> >>>>
> >>>
> >>>
> >>> --
> >>> Neil n
> >>>
> >>> Blog: tubaneil.blogspot.ca
> >>>
> >>> '88 Westy http://tinyurl.com/c8rlw6p
> >>>
> >>> '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
> >>>
> >>> Vanagon VAG *Gas* inline-VR Engine Swap Group:
> >>>
> >>> http://tinyurl.com/d7gd5ej
> >
> >
> >
> > --
> > Neil n
> >
> > Blog: tubaneil.blogspot.ca
> >
> > '88 Westy http://tinyurl.com/c8rlw6p
> >
> > '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
> >
> > Vanagon VAG *Gas* inline-VR Engine Swap Group:
> >
> > http://tinyurl.com/d7gd5ej
>