Neil,
In the late '70s the US govm'nt seemed to be reluctant to allow manual
chokes. They felt that owners would leave 'em on all the time, I guess.
Cars that got along fine for years with manual chokes were converted to
autochokes, and car that still had manual chokes would have auto-shutoff
mechanisms (I had a '76 Mazda Mizer with such a system, which I disabled --
heh-heh).
The Zenith Stromberg waterchoke was troublesome, I have been lead to
believe. Unless you need the original-looking parts for emissions
inspections (such as the poor souls in the Grand State of California) then
give your manual conversion another chance. Sounds as if you did a nice
installation! (Though some day, an FO [future owner] will undoubtably
curse you out for bypassing the instrument light dimmer!)
The Bentley manual specifies a fast-idle gap adjustment that I found does
not apply to the manual choke conversion. Sounds as if this is where your
conversion has failed.
The ZS has two idle speed screws: the main one (on mine) is a slotted set
screw with a 3/8th locknut. If you are sitting on the right front wheel,
it is just to the rear left corner of the carb. With the engine properly
warmed up, set this to provide a proper idle speed.
The fast idle screw is the spring-loaded regular screw just to the left of
the main idle setscrew. This should be adjusted to provide a 1500 to 2000
rpm reading when the choke is pulled all the way out (cold engine).
The "joker in the deck" is that when adjusted as I just said, the fast-idle
screw will affect the idle speed when the choke is 'off' too! On my car,
I varied the relationship between the two idle screws to get 1) a properly
fast cold (choked) idle and 2) a proper warm idle. Took some tweaking
over a few trips but I got it.
The other possibility is that your carb (or the used choke part anyway)
needs a rebuild. The gaskets and o-rings in the water choke are part of
the rebuild kit I got from Moss last year.
BTW, my conversion used the water choke's enrichment plate, sounds as if
yours is a factory manual choke...might be different than I have described.
Atwell Haines
'79 Spitfire
At 01:23 PM 10/28/98 -800, Neil McAllister wrote:
>Hi all,
>
>Well, I tackled the auto to manual choke conversion on the weekend with less
>than glorious results. The conversion went smoothly; I did have to tap one
>of the the bolt holes in the carb body which the manual unit needed (but the
>old water choke did not.) The new choke cable used the hole in the dash for
>my defunct and by-passed panel dimmer. With everything in place I started her
>up . . . barely; she wouldn't idle at all, ran rough as anything and leaked
>a moderate (not big) amount of gas out of the shaft on the manual choke unit
>(which was used and must have wear in it.) As far as I could tell, this unit
>wasn't doing any "choking" at all; perhaps it's not compatible with my carb?
>
>
>Well, after shutting the poor girl off and having a beer, I began to examine
>the automatic water choke; it appears to be in good condition, just missing
>a few key parts and screws(which I just ordered from Vicky Brit). In short,
>I'm going to give the water choke another try. When I bought the car the
water
>hoses had been by-passed from the choke for some reason.
>
>Sorry for the long post; any and all thoughts regarding the use of water
chokes
>would be greatly appreciated; is it worth resurrecting or more trouble than
>its worth?. I do have the Haynes Spitfire manual and one on carbs which are
>helpful.
>
>Thanks,
>
>Neil
>1980 Spitfire 1500 (Emma Peel)
>
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