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rustfree1967bug
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Joined: November 16, 2006
Posts: 3436
Location: minnesota
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 Posted: Sun Apr 30, 2017 7:31 am Post subject: Re: '74 bus seems to be running rich |
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They are 32/34 pdsit-3 carbs same as what i had before. Just that the chokes have been removed or they were never installed.
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'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
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'67 so-42
IDA's...well... they talk dirty -MURZI |
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Wildthings
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Joined: March 13, 2005
Posts: 50352
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| Posted: Sun Apr 30, 2017 8:44 am Post subject: Re: '74 bus seems to be running rich |
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| You can do a check of your mixture by just placing the palm of your hand over the air horn of each carb and seeing what effect slowing blocking off the air flow does. Do this at various throttle openings, for larger throttle opening you will need to set your palm across the air horn and then open the throttle quickly. This test is very subjective, but if the engine tends to stumble before you have blocked off most of the air horn the carb is running rich. |
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rustfree1967bug
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Joined: November 16, 2006
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Location: minnesota
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| Posted: Mon May 08, 2017 1:41 pm Post subject: Re: '74 bus seems to be running rich |
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Hooked up a fuel pressure gauge and i am getting right around 5-6psi. Is that too high?
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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rustfree1967bug
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Joined: November 16, 2006
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Location: minnesota
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| Posted: Mon May 08, 2017 1:47 pm Post subject: Re: '74 bus seems to be running rich |
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It also seems the engine dies down alot more when i choke the 3-4 side carb.
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Sat Jun 03, 2017 12:57 pm Post subject: Re: '74 bus seems to be running rich |
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Can anyone tell me the correct fuel pressure i should be running? I may try an inline regulator and see if that helps. Summer is flying by and i really want to drive my bus.
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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timvw7476
Samba Member
Joined: June 03, 2013
Posts: 2206
Location: seattle
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| Posted: Sat Jun 03, 2017 1:02 pm Post subject: Re: '74 bus seems to be running rich |
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5-6 psi can end up opening needles & seats you do want closed.
3 1/2 psi is the limit for a stock dual carb bus.(aftermarket pump)
I would keep it at 3 psi if I had a regulator.
If your top speed suffers at that setting, you will have to increase of course.
The factory manual did call for 5 psi or so, but the factory pump was also
speed sensitive, being run off the camshaft, didn't require a reg. like a
constant delivery electric pump. |
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Sat Jun 03, 2017 1:16 pm Post subject: Re: '74 bus seems to be running rich |
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My carbs aren't stock but are basically the same thing. And i running a stock fuel pump. It was a new old stock unit i installed about 5 years ago. The bus never did run perfect but it has gotten worse the last few years. I will try a regulator and see what happens.
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Sat Jun 03, 2017 4:05 pm Post subject: Re: '74 bus seems to be running rich |
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| If one side is worse then the other I would suspect a high float level or unequal jetting. |
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Tcash
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Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Wed Jun 21, 2017 2:58 pm Post subject: Re: '74 bus seems to be running rich |
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I just can't see how it can be the carbs since these are now a different set and they were supposed to run good on the bus they came off. Installed a fuel pressure regulator set to 2.5psi but i don't think it made a difference. Still get black/blue smoke out the exhaust when i rev it hard
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Wed Jun 21, 2017 3:30 pm Post subject: Re: '74 bus seems to be running rich |
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| There are only a couple of ways for extra gas to get into the engine, it either has to go through the carbs, or less likely via a bad diaphragm in a mechanical pump. If either of the needle valves are leaking then it is possible that fuel is getting into the engine when it is shut off and then being burned by the engine once it is started again thus causing a rich condition. |
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Wed Jun 21, 2017 3:37 pm Post subject: Re: '74 bus seems to be running rich |
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Wouldn't that last scenario only be an issue on start up then? I just am baffled that i switched the carbs to a completely different set and my issue did not go away. I'm ready to switch to a single centermount or something and see if that fixes it. Anything to get this thing back on the road.
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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Tcash
Samba Member
Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
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| Posted: Wed Jun 21, 2017 4:46 pm Post subject: Re: '74 bus seems to be running rich |
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| rustfree1967bug wrote: |
| just cruising around town it wants to sputter and almost seems like it keeps cutting in and out on a few cylinders. |
Did you look for high tension leaks?
Ignition High Tension Leaks
You can also do a cylinder balance test. If one of the cylinders is not dropping in rpm as much. Start Switching parts with a good cylinder one at a time, ie plug wire, plug. Spray for vacuum leaks.
Cylinder power balance (contribution) test
| rustfree1967bug wrote: |
| When i rev it up i get black smoke out the exhaust and it smells rich. Any ideas |
As Wildthings posted the oil could have gas in it, higher revs and combustion pressure can be forcing the contaminated gas past the rings and showing up as black smoke.
Pull the dipstick and smell it for gas.
Black smoke could be a tired engine also. Do a compression check. |
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lil-jinx
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Joined: August 14, 2013
Posts: 1109
Location: New Brunswick,Canada
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| Posted: Wed Jun 21, 2017 4:50 pm Post subject: Re: '74 bus seems to be running rich |
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Is the engine using any oil,is there any oil residue in the air cleaner,could be excessive base pressure,blue smoke is from oil,black smoke is over fuel or not enough air.
If you have not checked the timing in 5 years it may be the time to do that and maybe set the valves while your at it.
what are you runnig for an air cleaner and what have you done with the EGR
set-up.
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https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes. |
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Wed Jun 21, 2017 5:41 pm Post subject: Re: '74 bus seems to be running rich |
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I will check some of these things out tomorrow. There is no egr setup. I am just running a small air filter on the top of each carb. They came on the bus when i got it. I've messed with timing a bit but need to hook light up
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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lil-jinx
Samba Member
Joined: August 14, 2013
Posts: 1109
Location: New Brunswick,Canada
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| Posted: Wed Jun 21, 2017 6:37 pm Post subject: Re: '74 bus seems to be running rich |
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Plugged up air filter could make it run rich,and increases vacuum on the case vent which could cause it to suck in more oil vapour. take a run with the filters off to see if it changes any thing,
_________________
https://www.thesamba.com/vw/forum/viewtopic.php?t=620186
https://www.thesamba.com/vw/forum/viewtopic.php?t=668799
1974 Bay Westfalia. she likes to be called Ethel.
1968 Dune Buggy
1974 parts bus
A smart man learns from his mistakes,a very smart man learns from other's mistakes. |
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Thu Jun 22, 2017 2:03 pm Post subject: Re: '74 bus seems to be running rich |
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Compression test came back as follows
#1 155
#2 125
#3 125
#4 140
All the plugs except cylinder 4 look pretty sooty and black. Keep in mind these plugs are new with maybe 25 miles on them.
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
|
| Back to top |
|
|
lil-jinx
Samba Member
Joined: August 14, 2013
Posts: 1109
Location: New Brunswick,Canada
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Fri Jun 23, 2017 1:00 pm Post subject: Re: '74 bus seems to be running rich |
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No idea. It's always burned a small amount of oil. Engine was rebuilt somewhere around 70k ago according to the long term owner i bought bus from.
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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| Back to top |
|
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rustfree1967bug
Samba Member
Joined: November 16, 2006
Posts: 3436
Location: minnesota
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| Posted: Wed Jul 19, 2017 8:11 pm Post subject: Re: '74 bus seems to be running rich |
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Any opinions on those compression numbers? Going to adjust valves and try and set timing tomorrow. I don't have a tach so what is the correct timing for this engine with my svda?
_________________
'70 ghia
'69 ghia
'65 singlecab
'66 sunroof beetle
'74 bus
'67 so-42
IDA's...well... they talk dirty -MURZI |
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