| Author |
Message |
amikulics
Samba Member
Joined: July 21, 2017
Posts: 57
Location: San Diego
|
 Posted: Fri Jul 26, 2019 1:30 pm Post subject: PDSIT mixture settings |
 |
|
Hello everyone. I have made some progress since my last post but I've found myself stuck again on setting the mixture of my PDSIT carbs.
I am following the guide:
https://itinerant-air-cooled.com//viewtopic.php?t=7767
and I'm at step 4, syncing carb mixtures. I was able to do the finger on/off test successfully but I'm stuck at the second part where you disconnect solenoids.
With the central idle solenoid and retard line disconnected the engine idles at about 650, disconnecting the left solenoid drops the idle to about 600. However, disconnecting the right solenoid always kills the engine. I tried making the left carb richer but amskeptic said to make the adjustments by 1/4 turn and I have already made it richer by 1-1.5 turns so that didn't seem right.
Should I continue to make it richer or is there something else I should check on?
Lastly, amskeptic doesn't say whether to plug the mixture reference hose after the first half of step 4. I believe I'm supposed to leave it open and sucking air during the second half of step 4 correct?
Thanks for reading!
_________________
San Diego, CA
1973 VW Custom Camper
1979 Triple White Beetle |
|
| Back to top |
|
 |
aeromech
Samba Member
Joined: January 24, 2006
Posts: 17645
Location: San Diego, California
|
| Posted: Fri Jul 26, 2019 9:56 pm Post subject: Re: PDSIT mixture settings |
|
|
Good luck. We tried our best with those carbs and they are the hardest I’ve ever seen to get right. I wouldn’t do it again
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
|
| Back to top |
|
|
busdaddy
Samba Member
Joined: February 12, 2004
Posts: 52785
Location: Surrey B.C. Canada, but thinking of Ukraine
|
| Posted: Sat Jul 27, 2019 8:42 am Post subject: Re: PDSIT mixture settings |
|
|
| amikulics wrote: |
I tried making the left carb richer but amskeptic said to make the adjustments by 1/4 turn and I have already made it richer by 1-1.5 turns so that didn't seem right.
Should I continue to make it richer or is there something else I should check on? |
If going richer didn't help try it the other way, maybe it's too rich already?
_________________
Rust NEVER sleeps and stock never goes out of style.
Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!
Слава Україні! |
|
| Back to top |
|
|
xyzzy
Samba Member
Joined: March 24, 2014
Posts: 229
Location: Encinitas, CA
|
| Posted: Mon Jul 29, 2019 9:07 am Post subject: Re: PDSIT mixture settings |
|
|
| amikulics wrote: |
Hello everyone. I have made some progress since my last post but I've found myself stuck again on setting the mixture of my PDSIT carbs.
I am following the guide:
https://itinerant-air-cooled.com//viewtopic.php?t=7767
and I'm at step 4, syncing carb mixtures. I was able to do the finger on/off test successfully but I'm stuck at the second part where you disconnect solenoids.
With the central idle solenoid and retard line disconnected the engine idles at about 650, disconnecting the left solenoid drops the idle to about 600. However, disconnecting the right solenoid always kills the engine. I tried making the left carb richer but amskeptic said to make the adjustments by 1/4 turn and I have already made it richer by 1-1.5 turns so that didn't seem right.
Should I continue to make it richer or is there something else I should check on?
Lastly, amskeptic doesn't say whether to plug the mixture reference hose after the first half of step 4. I believe I'm supposed to leave it open and sucking air during the second half of step 4 correct?
Thanks for reading! |
Have you checked compression?
Have you verified fuel pressure?
Have you verified equal cylinder participation?
Have you checked for air leaks? Verify the mating surfaces of the carbs are flat, your booster elbows are not cracked, and there are NO air leaks anywhere!
Have you verified the floats? 12-14mm
Have you verified the needle valves arent sticking?
Have you verified the solenoids both work? If you dont have an extra set, try swapping solenoids and see if the problem reverses itself.
Do you have collars on your solenoids? Are the rubber grommets good? If you partially unscrew 1/4 turn the solenoid (after verifying its good) on the side that's not cooperating, does that alleviate the problem?
The solenoids should click with power removed but that doesn't necessarily mean its passing fuel correctly.
Where in San Diego are you?
_________________
-----
1973 VW Westfalia 2L hydraulic, dual Solex PDSIT
1987 VW Vanagon Westfalia |
|
| Back to top |
|
|
amikulics
Samba Member
Joined: July 21, 2017
Posts: 57
Location: San Diego
|
| Posted: Tue Jul 30, 2019 1:27 pm Post subject: Re: PDSIT mixture settings |
|
|
Following some of the advice I did the cylinder balance test by pulling plug wires one at a time and each cylinder dropped by the same RPM so I believe that is good. I also swapped the solenoids just in case one was bad but this didn't help it still dies when the right carb solenoid is disconnected.
_________________
San Diego, CA
1973 VW Custom Camper
1979 Triple White Beetle |
|
| Back to top |
|
|
airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 13491
Location: West Coast, USA
|
| Posted: Tue Jul 30, 2019 9:08 pm Post subject: Re: PDSIT mixture settings |
|
|
Are you using the Bentley manual "remove the carb/feeler gauge" method of setting the idle stop screws? Or are you using the IAC "1/4 Turn after contact" method?
Robbie
_________________
One-on-one tech help for your vintage Volkswagen:
www.airschooled.com
https://www.patreon.com/airschooled |
|
| Back to top |
|
|
xyzzy
Samba Member
Joined: March 24, 2014
Posts: 229
Location: Encinitas, CA
|
| Posted: Wed Jul 31, 2019 8:41 am Post subject: Re: PDSIT mixture settings |
|
|
The chances of fixing this problem without answering the questions below is going to be low. You verified equal cylinder participation now, and verified the problem persists when swapping solenoids...what about the rest?
Also, where in San Diego are you?
Have you checked compression?
Have you verified fuel pressure?
Have you verified equal cylinder participation?
Have you checked for air leaks? Verify the mating surfaces of the carbs are flat, your booster elbows are not cracked, and there are NO air leaks anywhere!
Have you verified the floats? 12-14mm
Have you verified the needle valves arent sticking?
Have you verified the solenoids both work? If you dont have an extra set, try swapping solenoids and see if the problem reverses itself.
Do you have collars on your solenoids? Are the rubber grommets good? If you partially unscrew 1/4 turn the solenoid (after verifying its good) on the side that's not cooperating, does that alleviate the problem?
_________________
-----
1973 VW Westfalia 2L hydraulic, dual Solex PDSIT
1987 VW Vanagon Westfalia |
|
| Back to top |
|
|
|
