I won I won I won! They don't spray gasoline any longer!
A while ago I complained about my SU's spraying gas out the vent's on
top of the bowls. I fiddled with them for ever it seems, and finally
temporarily gave up in disgust, putting the Stromberg back on. Well now
they're fixed, and it's an interesting tale, or at least it's
interesting to me.
I already had the Haynes carburetor book, but I also purchased the
complete set of manuals from Burlen Fuels or however that's spelled.
The people that now make SU carburetors. Lots of nifty information in
there! Everything you ever wanted to know about those colored bands on
the fuel tubes, why different jets are different colors, and all that
stuff. Made it real helpful when looking through piles of stuff at swap
meets too. Learned where some things on my carburetors weren't
"correct," though I didn't appreciate the significance of it at first.
To cut to the chase, I discovered that Spitfires require a special bowl
bushing of a dampening characteristic made only for Spitfires. Nasty
old black bushings, of which I have dozens, just don't cut it. I also
discovered that after market rebuild kits don't always have precisely
the right length bowl mounting bolts, so they don't provide the right
tension in holding the bowls against those special Spitfire only
bushings. And by jove there is *definately* a difference in how the
bowls are affixed when done correctly, with oem parts.
So I rebuild the carbs for the nine millionth time, and mounted them on
the car a few hours ago. No fuel spraying! Not only that, the car runs
phenomenally better then it did with the bowls improperly mounted using
generic rebuild kit parts and "good enough" bushings. I'd surmise that
the bowls were vibrating and flapping with the wrong bushings, resulting
not only in fuel spraying out the vent holes, but screwing up the fuel
mixture royally for the engine. Which made the engine run rough,
vibrating and flapping the fuel bowls even harder. Oh heck, there's no
surmising, that's exactly what the problem was.
Scouts honor (I was one once, until the police intervened, but that's a
different story), I started the car without setting the carburetors up
at all, and it purrs. All my linkages are lose, nothing is
synchronized, the jets are just screwed in and not matching in height,
the only thing right and matching are the float heights. Yet the car
runs much better then it ever did with the single Zenith, and far better
then I could ever get it to run with the SU's, using the wrong bowl
bushings. Oh I can't wait to find out how it runs when I can actually
use the gas pedal (it's not connected yet either)!
Moral of the story? Get the right bowl bushings (purple and beige), and
the right bowl mounting hardware. Wow! What a difference! How old are
your bowl bushings?...
You know, for the money I spent in learning this, I probably could have
installed fuel injection...
|