Dodgy bocar 34pict3 carb!

[strutt]

So, got the van back from the MOT, and all was working sweet as a nut

However, one of the ongoing issue i have had is to get a consistant idle!
thought i had it dialed, however when getting home today the van just wouldnt idle, so once AGAIN, i reset everything back to factory (book) settings. (2 1/4 turns)
Lots of fiddling later and its only half idling, the carb is question is a Bocar 34pict3......My initial thought was to keep fiddling and clean the buggar out, however im slowly thinking of going down the route of buying a Solex carb.

Any top tips out there, have done a bit research and just seem to be turning up something about the hole in the butterfly valve.
Its just getting really annoying not being able to pull up at a junction and knowing if the engine is going to die!

I believe the timing is ok, as all revving up fine and not too hot. plus i have pertronics.

cheers,
Luke

 

[lard]

So, got the van back from the MOT, and all was working sweet as a nut

However, one of the ongoing issue i have had is to get a consistant idle!
thought i had it dialed, however when getting home today the van just wouldnt idle, so once AGAIN, i reset everything back to factory (book) settings. (2 1/4 turns)
Lots of fiddling later and its only half idling, the carb is question is a Bocar 34pict3......My initial thought was to keep fiddling and clean the buggar out, however im slowly thinking of going down the route of buying a Solex carb.

Any top tips out there, have done a bit research and just seem to be turning up something about the hole in the butterfly valve.
Its just getting really annoying not being able to pull up at a junction and knowing if the engine is going to die!

I believe the timing is ok, as all revving up fine and not too hot. plus i have pertronics.

cheers,
Luke

Hi,

I had the same issues as you with my '71 - dieing on idle once warmed up, even though it would idle away fine for hours on the drive, soon as I got to the junction at the end of my road it would stall.....

I would also recommend checking you don't have a Loose/split servo pipe <- this was my problem, pipe was loose and cracked on the servo end, cut frayed end off and refit = sorted!

if you are changing then an OG Solex is a good option (though I went twin ICT's), just make sure that it doesn't have a leak on the bushes or it's already been re-bushed, there was a guy on VZi would would take a solex in exchange for a nicely refurbed one

 

[Cali_bay]

I had the same issue with a Bocar carb on mine, I swapped it out for a Solex and rebuild kit. I found that this then idled perfectly, and drove reasonably well last year, but I have a few new issue with this now with a big flat spot on load I'm running a Vac dizzy which has recently been rebuilt and appears to operated correctly. The carbs currently in pieces again, to see if I can find the fault :?:

Have you thought about the EMPI version. I've been wondering about this, but looking on the web theres mixed reviews. :? Does anyone run one of these without issue?

 

[67panel]

check what size idle jet is fitted,they come set for beetles and the jets are all wrong ,also the size of the air corrector will make a differance to idle or if its blocked.

 

[lard]

Empi version of the 34 pict 3? I've got one of those from JK, bought it as a spare/replacement when trying to track down my idle issues - it wasn't the carb in the end and since converted to ICT's so still have it kicking around with only 100 odd miles on it

If you want to borrow it to test and take your bocar carb out the equation then drop me a PM

 

[strutt]

How would i know if the incorrect idle jet is in?
although it did run fine when i first had the van!
It does seem a bit odd that the adjustment screws dont exactly do a lot!

Part of me just wants to get a new one to rule out the same old problem!
although taken up Lard's kind offer!

to be continued! Bloody van :lol:

 

[toxicbug66]

What dizzy are you running? If its a 009 and you are running a bocar too they make a bad combo. I dumped my bocar and bought a used solex took me a few minutes to get it running better once it was fitted. My 009 dizzy does make idling a little hit and miss. A blip of the throttle helps it settle down.

 

[71Westy]

Well it took me 2 years to get my Solex jetted well enough to run nicely through the rev range.

I too couldn't adjust the idle enough with the screw - so upped the idle jet from a 55 to a 60. That worked wonders and I could then adjust the idle mixture.
I upped the main jet to a 130, since in the cruise it appeared to be lean.
And I reduced the air corrector jet size (it works the opposite way) which improved the higher load/speed no end. Can't remember what I did - but I have it written down somewhere if you want me to look.

So all in all it had been running too lean. Seems just about perfect now looking at he plugs (ie a slightly rich mixture). MPG went from 18 to 27.

 

[strutt]

I have a 009 dissy, that seems to be ok the rest of the time, so was going to keep that as it is, as i have pertronics fitted (more expense to change!)

Hopefully with take the bocar out of the eqation very soon, and either opt for EMPI jobbie or a nicely rebuilt solex!

 

[toxicbug66]

Not wishing to hijack the thread but....71westy, if you have jetting details for the 34 pict 3 carb I'd be really interested to find out what finally got your bus running sweet.

Cheers
Rich.

 

[strutt]

Righty, im reporting back!

So this afternoon i fitted the carb i have kindly borrowed of Lard!
However the same damn problem persists!

Im going to check the valve clearences in the morning, scratching my head a lot!
I only have 2 weeks to sort this until stanford hall!

I may buy a larger idle jet or just buy a proper solex carb, could there be any other underlying issues!
Its jus odd that revving up and driving is fine.....and that the ecking thing used to be perfect :evil:

love/hate relationship!

I think this is the sort of time to think, what would Ozziedog do......? Have a beer! :lol: 8)

 

[67panel]

2 beers

 

[strutt]

soooooo, after some more research on the net and going over the points that you fellas gave me, turns out i need a larger idle jet!!!! :roll:

where can i purchase a new one from and what size would be required....60???
as my backup a guy on vzi has a solex for £30 gotta be worth a go for a spare.

cheers again!

 

[Harlequin]

where can i purchase a new one from ?

try....you will have to call
http://gowerandlee.co.uk/" onclick="window.open(this.href);return false;

 

[ZedBed]

I'm interested to know why, if it was running fine when you got it, you think the jets sre incorrect?

Perhaps you have an air leak somewhere. Maybe the top of your inlet manifold is bent with 40 years of people trying to find an air leak and over-tightening the carb - happens. Or all the other air leak places you've no doubt been through already...

 

[strutt]

I'm interested to know why, if it was running fine when you got it, you think the jets sre incorrect?

Perhaps you have an air leak somewhere. Maybe the top of your inlet manifold is bent with 40 years of people trying to find an air leak and over-tightening the carb - happens. Or all the other air leak places you've no doubt been through already...

I have had a look around for an air leak and tbh cant find anything although havent check the inlet manifold where it bolts onto the heads!

The idle has been a bit shit all along, but got round it by tweaking all sorts, Im still going to keep looking into this. But im hopfull its the idle jet!
I guess an air leak would show up when going throught the rev range? (excuse my ignorance if not).

Hopefully i can drive the van in confidence now! maybe :?

also any other tips on air leak hunting?
cheers

 

[ZedBed]

My point was more that it ran well, nothings been changed (unless the fairies have changed you jets) so summuts up.
Perhaps by upping the jets it will go better, but maybe that's because you'll have compensated for an air leak by giving it more petrol.

 

[strutt]

My point was more that it ran well, nothings been changed (unless the fairies have changed you jets) so summuts up.
Perhaps by upping the jets it will go better, but maybe that's because you'll have compensated for an air leak by giving it more petrol.

Good point ZedBed!
Ill use upping the jets as short term fix!
I guess im in denial about a leak :lol:
Ill track the buggar down, armed with a trusty can of spray!!!


ordered a '60' jet today,

 

[lard]

Righty, im reporting back!

So this afternoon i fitted the carb i have kindly borrowed of Lard!
However the same damn problem persists!

Im going to check the valve clearences in the morning, scratching my head a lot!
I only have 2 weeks to sort this until stanford hall!

I may buy a larger idle jet or just buy a proper solex carb, could there be any other underlying issues!
Its jus odd that revving up and driving is fine.....and that the ecking thing used to be perfect :evil:

love/hate relationship!

I think this is the sort of time to think, what would Ozziedog do......? Have a beer! :lol: 8)

Gutted that the carb didn't make a difference - one more thing that comes to mind re: air leak - as it's a 71 I assume you have a servo?

Have you tried removing the servo pipe and plugging the servo take off on the inlet manifold? might be a loose/split pipe and doing this will take an air leak in the servo/pipes out of the equation.

 

[geenjay]

sounds to me like youve got an air leak it doesnt always show when you go up the rev range i would get a can of wd 40 [ive always used easy start,but not everyone is comfortable with spraying it around the engine bay] and spray around the usual suspects inlet manifold gaskets, rubber manifold connection pipes ,carb manifold gasket,if the revs go up or it starts spluttering/dying then bingo youve found it this is best done on tickover if youve swapped carbs for one you knows is working then it cant really be jet sizes... :mrgreen: