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Yes you did, and I was reading the carb port just to verify if the idle holes were still uncovered after I redid the lean-best idle procedure. At 1 1/2 turns (and 2 1/4 turns out on the mixture screw) the engine only idles at ~650 (vacuum at <1"). To increase idle rpm to ~850 and smooth it out requires 2 turns in, which then increases the vacuum to 4".
The manifold vacuum is another issue. With the carb port blocked (and both distributor ports blocked), manifold vacuum flutters between 16" - 20". Turning the idle screw in another 1/4 turn (now at 2 1/4 turns) the rpm increases to ~1000, vacuum holds steady at 21", but the carb port vacuum also increases.
So isolating the carb from both distributor diaphragms seems to indicate the vacuum leak is at the carb, or even the brake booster as Opelbits mentioned.
As I understand, I'm shooting for ~850 idle rpm (warm, choke off), 0" carb vacuum, and ~20" manifold vacuum. Is that about right?
Not so uncommon in my experience. That’s about where mine sits with zero vacuum at the port at 3° of ignition timing with things set up properly. I’ve done backflips trying to figure out why. I got away with what you’re doing on my old 1.9, no problem other than the occasional feathering on the gas pedal off idle due to periodic off idle stumble.

Since my 2.0 doesn’t like it and diesels upon shutting down the engine I’ve been pushed into better habits and I must say it’s paid off. I have it set up by the book now and by doing so all but eliminated the off idle stumble and moves through the progression stage much better. I had to modify the distributor by limiting my mechanical advance so I can get it to idle at 850 rpms,14° at idle gets it there, no less.

Your manifold vacuum sounds healthy, at 850-900 rpms my old 1.9 pulled 17”, my recently built 2.0 pulls just over 18”, raising the rpms boosts it up to 21”. I consider that healthy.

Keep up the good work.
Can you describe how you seem to be running too rich? How is the gas mileage?
 

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1969 Opel GT 1.9L.
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Discussion Starter · #22 ·
I haven't been tracking the mileage. The indicators of running rich are black soot blown out the tailpipe at startup and the spark plugs were sooty. Plus it smells rich at idle. Otherwise the engine idles nicely at 850 and the car drives fine.
Aside from this, last weekend I installed a new drivers-side linkage grommet; the old one had disintegrated. Since the linkage had to be disconnected anyway, I removed it all and cleaned it up and greased the ball & sockets.
I'm going to keep fiddling with the vacuum while search for a canister. Your input and the others have given me a much better understanding of what to diagnose. This weekend I'm going to pull the airhorn again and look at the power valve.
 

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Detritus Maximus
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If it's running decently, I would say the power valve is fine. Maybe see if there is any crud in the valve in the bottom of the fuel bowl. It might be leaking a little there.
 
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1969 Opel GT 1.9L.
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Discussion Starter · #26 ·
I finally got around to changing out the advance. Pretty straight forward, was able to swap it out with the distributor in the car; just had to loosen he retard cannister because the advance arm lays underneath. The longest part of the swap was having to find the cannister screws when they fell down the engine while tightening.

It's probably been 40+ years since I last used these mini-screw holders, not since I quit installing points in the late 70's/early 80s.

With Halloween night approaching we didn't have time to go a long shake down test, but the Opel ran good through town. The test will part-cruise on the freeway to see if the surging stopped.
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Discussion Starter · #27 ·
So I'm coming to the conclusion that 20 years experience with American V8 engines doesn't translate over to the Opel 1.9. Since swapping the advance cannister, the engine won't start unless I shoot starter fluid down the primary. Then it fires right up. The primary jet sprays fuel and the choke is working. So even though I didn't touch the distributor during the cannister swap, I wonder if the mechanical advance weights shifted and advanced the initial timing. I checked the timing with my timing light, but I can't make out the dot on the flywheel to line it up to the pointer. It makes me appreciate the harmonic balancer timing marks on V8s all the more. Is there a tip to being able to view the timing? My other thought is to find static TDC using the piston-stop method, hand rotating the engine CW and then CCW to find true TDC and then shining a light in the timing hole to find the dot.
 

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I'm not sure if this is helpful to you or not but I was able to mark mine with my finger extender and a silver sharpie.
I hit it first with brake clean and blew it off then got to it with the sharpie
I jacked up one wheel and in 4th gear turned the wheel to turn the engine until I could see the dot on the flywheel. ( a trick someone on here shared) sorry I forget who it was but it worked well
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Can Opeler
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I can't take credit for that, And I've tried searching for who and where gave me the Idea (thank you member)
It definitely made it much easier than trying to do it the hard way lol
Might have been me. The 4th gear method is my go to if the car is on the ground. If it’s on Jack stands I tighten down the alternator belt extra tight and turn the engine with the cooling fan (mine is metal this might not work with a plastic fan without removing plugs.)
 

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Detritus Maximus
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Once you find true TDC...forget the timing ball and pointed. Make your own paint dabs on the crank and the timing housing
 

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Discussion Starter · #34 ·
Did not see it else ware so an FYI, the factory ran the power for the choke from the back side of the horn. This is also a good place to get power for a Petronix.
BTW, this is another issue on the To Do list. The PO ran the power to the + coil stud. But its also been that way since we bought the car so while the wire needs to be re-routed, it's not the cause of the hard start issue.
 

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Do both. Easiest way is to modify what Kyler said about jacking up the rear, spin the tire with the spark plugs out, have someone shine a flashlight at the hole in the bellhousing, when the ball bearing lines up with the pointer. Stop. Mark the ball bearing on the flywheel, with "The finger extender", put a mark on the lower pully in front.(most file a notch), and mark the timing chain housing, and last but not least on your distributor housing. You should already have a notch there, I think. Hth.
 

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spin the tire with the spark plugs out
Exactly what I did to ensure cylinder N# 1 was near tdc which actually made it easier to see/find the dot on the flywheel.
It also gave me chance to use my camera probe to look at the cylinder walls and tops of pistons.( I was already in there) lol
 

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Discussion Starter · #39 ·
I'm not sure if this is helpful to you or not but I was able to mark mine with my finger extender and a silver sharpie.
I hit it first with brake clean and blew it off then got to it with the sharpie
I jacked up one wheel and in 4th gear turned the wheel to turn the engine until I could see the dot on the flywheel. ( a trick someone on here shared) sorry I forget who it was but it worked well
View attachment 439426 View attachment 439427
And noticed two additional essential tools on your workbench: cheater glasses and the TV remote.
 
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