| Author |
Message |
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
 Posted: Mon Dec 23, 2019 4:18 pm Post subject: Carb jetting? Car runs rough |
 |
|
I have a 61 completely stock, 1200cc motor with a 28PICT carb (not the 28PICT1). When I start the car and the choke is on the car idles and rev's up nicely, but as soon as the automatic choke kicks off it sounds like it is maybe misfiring (NOT positive not this), however, if I hit the throttle quickly it kinda sputters a bit before it revs up. If I slowly give it throttle it will Rev up.
The carb was cleaned, vacuum working, so I don't think there is a problem there.
I'm wondering if I should try a different main jet. Would that be the problem? What size jets should go on this carb?
Thanks |
|
| Back to top |
|
 |
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Mon Dec 23, 2019 6:00 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
Does the accelerator jet/nozzle spray properly or kind of dribble when the throttle arm on the carb is pulled back??
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Mon Dec 23, 2019 6:10 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
Yes, I can see gas squirting in when I pull the throttle back.
It currently has the 55 jet in the carb. I tried a 60 and a 65, but there was no difference. As soon as I step on the pedal, it stutters until it hits a higher RPM. Once it gets to a high RPM it runs great. Only problem is on the lower RPMs.
| Eric&Barb wrote: |
| Does the accelerator jet/nozzle spray properly or kind of dribble when the throttle arm on the carb is pulled back?? |
|
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Mon Dec 23, 2019 6:54 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
| txasylum wrote: |
| Yes, I can see gas squirting in when I pull the throttle back. |
Is the accelerator jet/nozzle aimed so it sprays between the throttle butterfly and carb throat wall, when that valve opens up?
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Mon Dec 23, 2019 7:03 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
| txasylum wrote: |
It currently has the 55 jet in the carb. I tried a 60 and a 65, but there was no difference. As soon as I step on the pedal, it stutters until it hits a higher RPM. Once it gets to a high RPM it runs great. Only problem is on the lower RPMs.
|
Which jet?? Guessing the pilot/idle jet, and that one only affect the idle, not the just above idle.
Accelerator jet/nozzle is supposed to inject fuel in the small RPM range when going from idle to main jet.
Main jet has more to with how much power you have once you stop pressing the pedal down anymore.
Air correction jet is supposed to at higher RPMs to lean out the flow of fuel from the main jet, by letting air bubble into the main jet fuel flow.
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Mon Dec 23, 2019 7:10 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
It looks to be in the correct location. I looked at another carb I have. Here is sa picture.
| Eric&Barb wrote: |
| txasylum wrote: |
| Yes, I can see gas squirting in when I pull the throttle back. |
Is the accelerator jet/nozzle aimed so it sprays between the throttle butterfly and carb throat wall, when that valve opens up? |
|
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Mon Dec 23, 2019 7:12 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
So should I adjust the accelerator jet? I just read a manual on 28PICT. Doesn't look like the accelerator pump is adjustable.
| Eric&Barb wrote: |
| txasylum wrote: |
It currently has the 55 jet in the carb. I tried a 60 and a 65, but there was no difference. As soon as I step on the pedal, it stutters until it hits a higher RPM. Once it gets to a high RPM it runs great. Only problem is on the lower RPMs.
|
Which jet?? Guessing the pilot/idle jet, and that one only affect the idle, not the just above idle.
Accelerator jet/nozzle is supposed to inject fuel in the small RPM range when going from idle to main jet.
Main jet has more to with how much power you have once you stop pressing the pedal down anymore.
Air correction jet is supposed to at higher RPMs to lean out the flow of fuel from the main jet, by letting air bubble into the main jet fuel flow. |
Last edited by txasylum on Mon Dec 23, 2019 7:18 pm; edited 1 time in total |
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Mon Dec 23, 2019 9:58 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
| txasylum wrote: |
It looks to be in the correct location. I looked at another carb I have. Here is sa picture.
|
Location does not matter, it matters if the squirt of fuel goes down the slightly open throttle valve.
That early of carb has no accelerator pump adjustment.
_________________
In Stereo, Where Available!
Last edited by Eric&Barb on Tue Dec 24, 2019 9:15 am; edited 1 time in total |
|
| Back to top |
|
|
thomas.
Samba Member
Joined: July 31, 2010
Posts: 1290
Location: South West (Pa.)
|
| Posted: Tue Dec 24, 2019 3:24 am Post subject: Re: Carb jetting? Car runs rough |
|
|
| You might need to adjust the choke some now that the weather has gotten colder. |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 5:09 am Post subject: Re: Carb jetting? Car runs rough |
|
|
That's the question. How do I adjust it? What do I adjust.
| thomas. wrote: |
| You might need to adjust the choke some now that the weather has gotten colder. |
|
|
| Back to top |
|
|
andk5591
Samba Member
Joined: August 29, 2005
Posts: 16757
Location: State College, PA
|
| Posted: Tue Dec 24, 2019 5:35 am Post subject: Re: Carb jetting? Car runs rough |
|
|
You loosen the 3 screws holding the choke element and rotate it slightly (mark your initial position) so that is stays open longer. Here is the question though - once the car fully warms up (like after 5 or 6 minutes) is it the same or does it improve? If it is fine after fully warming, then yeah, adjust choke. If not, I suspect you still have crap in the carb.
BTW, is this a new problem or is the car new to you?
_________________
D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them... |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 6:02 am Post subject: Re: Carb jetting? Car runs rough |
|
|
It gets worse as the choke shuts off. I bought this car a few weeks ago and it came with this problem. I did take carb off and cleaned it.
| andk5591 wrote: |
You loosen the 3 screws holding the choke element and rotate it slightly (mark your initial position) so that is stays open longer. Here is the question though - once the car fully warms up (like after 5 or 6 minutes) is it the same or does it improve? If it is fine after fully warming, then yeah, adjust choke. If not, I suspect you still have crap in the carb.
BTW, is this a new problem or is the car new to you? |
|
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 8:13 am Post subject: Re: Carb jetting? Car runs rough |
|
|
Making progress. Took the carb off again inspecting and cleaning. Found the accelerator pump was blowing bubbles around the gasket. put another on there and it seems to have helped the problem. Not as bad. Going to adjust carb a bit more, maybe new plugs, points, condenser. Hope that solves it all.
| txasylum wrote: |
It gets worse as the choke shuts off. I bought this car a few weeks ago and it came with this problem. I did take carb off and cleaned it.
| andk5591 wrote: |
You loosen the 3 screws holding the choke element and rotate it slightly (mark your initial position) so that is stays open longer. Here is the question though - once the car fully warms up (like after 5 or 6 minutes) is it the same or does it improve? If it is fine after fully warming, then yeah, adjust choke. If not, I suspect you still have crap in the carb.
BTW, is this a new problem or is the car new to you? |
|
|
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Tue Dec 24, 2019 9:26 am Post subject: Re: Carb jetting? Car runs rough |
|
|
| txasylum wrote: |
| Making progress. Took the carb off again inspecting and cleaning. Found the accelerator pump was blowing bubbles around the gasket. put another on there and it seems to have helped the problem. Not as bad. Going to adjust carb a bit more, maybe new plugs, points, condenser. Hope that solves it all. |
While you had the carb off, did you check if the accelerator jet shoots thru the throttle valve as it just opens?
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 9:32 am Post subject: Re: Carb jetting? Car runs rough |
|
|
Yes, I cleaned it up and made sure it was squirting fuel into the carb.
| Eric&Barb wrote: |
| txasylum wrote: |
| Making progress. Took the carb off again inspecting and cleaning. Found the accelerator pump was blowing bubbles around the gasket. put another on there and it seems to have helped the problem. Not as bad. Going to adjust carb a bit more, maybe new plugs, points, condenser. Hope that solves it all. |
While you had the carb off, did you check if the accelerator jet shoots thru the throttle valve as it just opens? |
|
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Tue Dec 24, 2019 9:48 am Post subject: Re: Carb jetting? Car runs rough |
|
|
| txasylum wrote: |
Yes, I cleaned it up and made sure it was squirting fuel into the carb.
| Eric&Barb wrote: |
| txasylum wrote: |
| Making progress. Took the carb off again inspecting and cleaning. Found the accelerator pump was blowing bubbles around the gasket. put another on there and it seems to have helped the problem. Not as bad. Going to adjust carb a bit more, maybe new plugs, points, condenser. Hope that solves it all. |
While you had the carb off, did you check if the accelerator jet shoots thru the throttle valve as it just opens? |
|
Good, but is it AIMED properly???
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 10:20 am Post subject: Re: Carb jetting? Car runs rough |
|
|
I believe so. As it opens it should shoot down the tube, right? I'll have to verify that.
| Eric&Barb wrote: |
| txasylum wrote: |
Yes, I cleaned it up and made sure it was squirting fuel into the carb.
| Eric&Barb wrote: |
| txasylum wrote: |
| Making progress. Took the carb off again inspecting and cleaning. Found the accelerator pump was blowing bubbles around the gasket. put another on there and it seems to have helped the problem. Not as bad. Going to adjust carb a bit more, maybe new plugs, points, condenser. Hope that solves it all. |
While you had the carb off, did you check if the accelerator jet shoots thru the throttle valve as it just opens? |
|
Good, but is it AIMED properly??? |
|
|
| Back to top |
|
|
Eric&Barb
Samba Member
Joined: September 19, 2004
Posts: 24732
Location: Olympia Wash Rinse & Repeat
|
| Posted: Tue Dec 24, 2019 10:36 am Post subject: Re: Carb jetting? Car runs rough |
|
|
| txasylum wrote: |
I believe so. As it opens it should shoot down the tube, right? I'll have to verify that.
|
It should shoot out the jet and down the throat of the carb. At the very bottom of the carb there is a butterfly valve that is just opening when you start pulling the throttle arm back by hand. That accelerator nozzle spray needs to hit right at that opening JUST as it opens. Not spraying on the side of the carb throat wall, not on top of that butterfly valve, or anywhere else.
_________________
In Stereo, Where Available! |
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 11:01 am Post subject: Re: Carb jetting? Car runs rough |
|
|
It does seem to be doing what you described.
| Eric&Barb wrote: |
| txasylum wrote: |
I believe so. As it opens it should shoot down the tube, right? I'll have to verify that.
|
It should shoot out the jet and down the throat of the carb. At the very bottom of the carb there is a butterfly valve that is just opening when you start pulling the throttle arm back by hand. That accelerator nozzle spray needs to hit right at that opening JUST as it opens. Not spraying on the side of the carb throat wall, not on top of that butterfly valve, or anywhere else. |
|
|
| Back to top |
|
|
txasylum
Samba Member
Joined: December 15, 2004
Posts: 389
Location: Boyers, PA
|
| Posted: Tue Dec 24, 2019 5:36 pm Post subject: Re: Carb jetting? Car runs rough |
|
|
Just when I thought it was starting to run better, well that was sitting in the garage. I just drove it down the driveway. Coming back up it I couldn't get it to run in second gear without a lot of sputtering. One thing I noticed as it sat running in the garage is that the intake frosts up. I'm not sure that has anything to do with it. Runs great when it is cold and choke is on. Once warmed up and choke kicks off is when goes downhill.
| txasylum wrote: |
It does seem to be doing what you described.
| Eric&Barb wrote: |
| txasylum wrote: |
I believe so. As it opens it should shoot down the tube, right? I'll have to verify that.
|
It should shoot out the jet and down the throat of the carb. At the very bottom of the carb there is a butterfly valve that is just opening when you start pulling the throttle arm back by hand. That accelerator nozzle spray needs to hit right at that opening JUST as it opens. Not spraying on the side of the carb throat wall, not on top of that butterfly valve, or anywhere else. |
|
|
|
| Back to top |
|
|
|
