Title day today! (I took the day off work to get the title, and to have a washing machine delivered )
In preparation for title day, I thought I'd give that carb a go. I sprayed brake cleaner all over the place trying to find a vacuum leak but alas, there weren't any. It dawned on me that since this only happened when the car's coolant temp needle was at 80deg c or below, it was probably a problem with the cold start circuit.
Except I have no stinking idea how the cold start circuit works on this carb. Unlike any other carb there isn't an exposed choke butterfly anywhere! Good thing I have my trusty book and practice carb!
(Oh yeah, on "car insurance day" I bought a binder for my manual finally)
I figured I could just find the adjustment procedure in the "fuel" chapter, but I thought maybe there might be a quick and dirty description of how to adjust the choke here. The idea of the troubleshooting section is pretty simple, you read a description of a problem and it sends you to a lettered bullet point that tells you what to do to fix it.
I thought "Engine misfires, low speed", and "engine misfires on acceleration and fails to rev" would be good ones to go off of. From there I'd take the letters that were common between the two and go from there.
I don't think you're ready for this. Are you ready?
The letters the two faults had in common were "E-F-I"
Those Germans have a sick, sick sense of humor...
Ok enough with that. Lets go to the fuel section and see what it says:
The book is already off to a bad start with me because it is rather insistent that I have a choke cable (mine is an aqua choke). Then it goes on to say I should actuate the choke (via the cable) and then adjust some sort of stop until it is 1mm away from some arm. (photo'd below around the little letter b). I dont see any of this on my practice carb...
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Instead I have an arm like one I'd expect to see on any other normal carb's automatic choke system. Mine has the aqua housing and bi-metalic coil removed already but I'm familiar enough with its operation that I can picture how it works.
Basically the bi-metalic coil spring pulls that arm to the right to actuate the choke. I can use my fingers for that part and just see what happens from there. So I push some slight pressure on the arm, blip the throtte, and...
That's when I notice movement in that little window! That must be where the choke magic happens!!
3-screws later:
Boom. There is the cam I was hoping for.
So there still isn't a butterfly or anything like in carbs I'm more familiar with, but at least I've found the part that makes the idle higher. It looks like the cam actuates the "fast idle" and the arm there threads out to increase or decrease the fast idle speed. This wont solve my cars coughing when I try to accelerate before it's fully warmed up but maybe this'll keep me from stalling while idling in traffic again.
Now I feel comfortable enough to tinker on the real deal so out to my car I go. Here's my starting point (I ended about 3/4 rich)
Unfortunately while in there I noticed the little piece of foam that was plugging what I think was originally a PCV port is missing in action (maybe one of those coughs blew it out? maybe it got sucked in?)
So out came the spare parts.
Unfortunately it's kind of picking the lesser of two evils. Both have ports that arent going to be used, both are cut to some degree, it's just a matter of which one I think is going to do what I need it to. Already I'm thinking of using my extra because it has room for clampage. Apparently whatever I put in next is going to need a bit more positive engagement than what it had before.
I made a plug by slicing down the center of a section of hose and rolling it into itself. It's not quite perfect but it's almost completely sealed. I used my last zip tie at the base to help squeeze it. I'll snag a couple more later today to finish it off. Then I installed the boot upside down to hide the gruesome patch. Easy money
Oh and thanks to a dropped screw, I found my foam! It's not in the engine, yay!!!
(for the record, that's the previous owners work. it's all his fault )
Good times