PDSIT Tuning using Amskeptic's Factory Procedure - problems

[Hashfiction]

So, I might be becoming a regular question asker here it seems... Hopefully one day I'll be able to give back!

I'm using Amskeptic's Procedure to tune my Dual Solexs, and I have been following it to a Tee. I haven't been having much luck, unfortunately.

Background on the the Carbs: fully rebuilt with throttle bushings replaced. All the right stuff on it. only problem is the right throttle screw has been pushed in too far by someone (GRRR, PO..) but it isn't too bad.

I have started out with an Idle Speed WAY too high (1500ish, but varies wildly sometimes), and it's been a game to get it down to the speeds he wants. But I succeeded by blocking off the Central Idling Circuit with my finger, not fully but just enough. I do have the CIC cut-off solenoid engaging with the plunger, but just that doesn't seem enough.

Now though, I have been trying to synchronize the carburetor mixtures. I have used the finger on/off method and got to the fabled "No Change". However, once I try to see what the individual carburetor contributions are, things get messy.

I pull the left hand idle jet cut-off solenoid and the rpm drops to 900ish rpm from about 1500rpm

I plug the left back in and pull the right hand solenoid and the engine dies.

What could be causing the engine to die?


I'm terribly sorry for the novel I can shorten it if requested. I will be posting this to the Itinerant air cooled forum, hopefully. I will update this post with a link.

Thank you for any help you can offer!
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[busdaddy]

[Amskeptic]

[Hashfiction]

Amskeptic, I'm back with a healthy reassurance that my brake booster elbows are in good order. (checked fit and they were just purchased from German supply).

A) Idle is still high. Seems to be around 900 for warm up period but when chokes fully open it increases in speed to 1200-1500 rpm. I'm not unsure if that information matters.
1.Throttle stop screws are adjusted properly, using your method and confirmed with a feeler gauge when the carbs were off.
2. Vacuum retard unit works. can feel vacuum signal coming from engine and the unit hold vacuum when applied

B) I checked that the central idling unit was off by bottoming both speed and mixture screws. it changed the idle speed by quite alot so I assume the solenoid wasn't closing it off completely. I did the next test with the screws bottomed out

C)
1. left mixture screw needed 1 3/4 turns to seat returned.
2. right mixture screw needed 2 1/4 turns to seat. returned.
3. No turns for CIS screw because it's bottomed out as it is.


Thank you for the help!
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[Hashfiction]

Might have been stupid not to post this to begin with, I feel meek...

When I go on to synchronize the carb mixtures, the instructions say to disable CIS (Done) and pull Vacuum retard from vacuum can. Here's what happens:

CIS disabled, Retard on: 1210 RPM
CIS disabled, Retard pulled: 2410 RPM
CIS disabled, Retard pluged back in: 1700 RPM

This isn't all what the instructions say should happen.

I think I have a case of 'I'm lost's'
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[busdaddy]

Have you waited for the chokes to fully open and then quickly opened the throttle once so the fast idle cams disengage?
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[Hashfiction]

Busdaddy, I have been doing that, but just tested it to be sure. Here are the readings.

Chokes open fully: 1100ish rpm

Touch throttle once: 1500ish rpm and stays that way.

It seems that if the rpm increases, it doesn't want to come back down. That just a humble observation though.

Liam
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[busdaddy]

How about if you disconnect both carbs from the crossbar linkage? Lots of slack in your throttle cable? What year Solexes are we discussing?, do they have the long return springs down to the tin?, or the short ones attached to the little arms on the carbs?
_________________
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!

[Hashfiction]

I believe them to be 1974 solex, they have the small Springs to the little arms. The accelerator cable has reasonable tension, not loose goose. I have just disconnected the crossbar linkages to no effect. Same problem.

I must profusely thank you for this though! It really means a lot to me!
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[busdaddy]

No problem,
So we've ruled out the linkage as the cause for a high idle, now lets discuss vacuum leaks and just how you set the gap on those throttle plates when they were off....
Lets begin with backing out each throttle stop screw 1/2 turn, be accurate, you need to be able to return to your baseline setting if needed, log every turn done to anything. If that makes no difference on the idle speed put them back. Now spray carb cleaner around the bases of the carbs as well as any other joints in the vacuum system, does the idle speed change when you spray a particular spot? No carb cleaner?, water in a trigger bottle will do as well but the idle will drop when you find the leak opposed to increase.
_________________
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!

[Hashfiction]

I turned the throttle stop screws be half a turn and got a slight drop on idle, nothing crazy though, only about 50 rpm.

I sprayed carb cleaner on all the rubber connections and the carb bases. When I sprayed the left carb bsse I got a slight increase. I assume it's because there's a leak there. I have a 1/64 gasket, and phenolic gasket, and a 1/64 gasket on the base. Do you think I should increase gasket thickness, or recut anther with the same thickness?

Another note, I have the rectangular plates with a some of holes in them, connected to the carb base. I think they were part of the song network, but I'm not sure. I'm trying to upload pictures. are these supposed to be blocked Off, could they be causing the vacuum leak?


Another note, I notices a liquid dripping from Both accelerator pumps, I stuck a screwdriver in the throat to catch a drip and it smells like gas. Is this a normal thing?

Thanks!
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[Hashfiction]

Hidden between the spring and the linkage

The most not blurry part. (sorry)
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT

[Amskeptic]

[Hashfiction]

This is what it looks like under the air cleaner. The blocked off pipe could be anit backfire valve you speak of.

Do I need to block them off?

I agree with what you say on the throttle mixture screws, however, my carbs (Without the CIS) do not come anywhere near that low by themselves at idle. they are running somewhere 1300ish rpm. As you probably read, busdaddy is attempting to help me solve that.

So I will attend to the the mixture balancing when i can get my idle to a bit lower, (aiming for your 600-800 rpm) if thats a good idea. Also when balancing the mixtures, I should have both the CIS AND the retard pulled, right?

By the way, do you have ideas on what could be causing this:

[busdaddy]

Assuming you don't currently have an air pump the blocked off port likely supplied that. Just where in YVR are you?, PM me your number and I'll call you in the AM.
_________________
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!

[busdaddy]

Phone consults have yielded some good progress, variables eliminated and idle under control now, Hashfiction is now revisiting Colin's matrix, I expect him to post results when he's reached carb nirvana, sounds like he's close
_________________
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!

[Hashfiction]

So, after checking vacuum leaks EVER WHERE. Blocking off the brake booster. Checking the old egg ports on the manifolds (found a leaky gasket there). Systematically blocking off the CBS and balance tube. (I can go into more detail if anyone wants, just ask!). I was unable to get my Idle down. So, over the the phone Busdaddy gave the suggestion to put a pop rivet in the hole in my throttle plate because I am using an older distributor (from 1972) with less retard than stock. Worked like a charm, down to about 8-1000rpm! But... fixed it for a couple days only, and the high Idle was back.

Though today, I discovered my fuel was boiling in the hose (I could see it in the fuel filter on the way to the pump) because it was running to close to the vent on the heat exchanger. So I routed the line above the starter and tyranny, instead of beanth them (does this sound correct?). It hasn't really been giving me grief since, (but who knows...) so I started with Amskeptic's Tuning Matrix.

I have gotten as far as adjusting the mixture screws. I can't seem to get the idle down to 6-800 rpm. It stays put at 950ish but I continued with the matrix to see what would happen. Now, when I pull the right cut-off solenoid the idle drop to about 510 rpm. But when I pull the left cut-off solenoid, it doesn't drop at all. The CIS is completely off, by turning down the two screws.

Any ideas?

Thank you!

P. S. I really owe Busdaddy for those phone calls, seriously, they brought light to the end of my tunnel. Thank you!
_________________
"Mars" (as per the rust)
1974 Chassis Manual 1700cc (out of a type 4) Dual Solex 32/34 PDSIT