Puzzle this "Americanism?" out
I'd like to know what it possibly referred to in the phrase "The answers a lemon" meaning nothing could it be to the symbols on a one armed bandit? I doubt it was an unreliable car? (I'd say that came much later)
Google only had 2 hits on this but for a phrase on a different subject
Any Takers?

From A Dictionary of Australian Words and Terms by Gilbert H. Lawson:

"ANSWER IS A LEMON - A meaningless reply."

The source is from a pdf file, for which you will need Adobe Acrobat reader:

http://setis.library.usyd.edu.au/ozlit/pdf/p00024.pdf

Ulysses, Chapter 15:

MRS BREEN
(to Bloom) High jinks below stairs. (she gives him the glad eye) Why
didn't you kiss the spot to make it well? You wanted to.
BLOOM
(shocked) Molly's best friend! Could you?
MRS BREEN
(her pulpy tongue between her lips, offers a pigeon kiss) Hnhn. The
answer is a lemon. Have you a little present for me there?

And... titles of the BBC comedy 'The Vital Spark' on this page include "The Answer's a Lemon" (1967).

As Coldfuse says, it seems to be a way of giving a non-reply. It also seems to be a way of mocking someone who is saying something obscure or complicated - you can interrupt with, "The answer's a lemon!". It doesn't seem to be particularly American, though.

Thanks for trying 'Fuse
But that says word for word all I know about it
Perhaps Maiku has heard of it?

newnickname
I have never heard of it before,
As regards Lemon (other than fruit)the only times we ever use in in everyday speech (UK?) is picking up something (small child) and calling it a "Heavy-Lemon" no reference on Google (defeated it! )
Never heard it used in common use when referring to a bad car ect car dealers do use it (rarely)and occasionally heard on TV drama progs.(from the States)LOL

I'd never heard it before either. I read 'Ulysses' (finally ) recently, but didn't notice the phrase. 'The Vital Spark' was set in Argyll, I think. The writers must have thought "the answer's a lemon" was commonly recognised, if they felt they could use it in the title.

It sounds to me - just guessing - like a catch phrase from a Victorian or Edwardian parlour-game, along the lines of 'animal, vegetable or mineral'.

Another reference from the net, this time from an Old Bailey judge:

Judge King-Hamilton punctuated the trial with trivial comments. At one point, after a tense series of questions, he announced the latest England Test cricket scores. At another point, after some turgid prosecution questioning of Denis Lemon, he airily interjected with the phrase "the answer's a lemon!" He looked around the court for signs of appreciation of his humour.

From phrases.shu.ac.uk:

Posted by R. Berg on March 02, 2001 at 18:52:03:
In Reply to: the answer's a lemon posted by James Briggs on March 02, 2001 at 18:15:00:
: 'The answer's a lemon' is a saying common in British English. It is used as a response meaning 'nothing doing' when asked a question which is regarded as unreasonable or ridiculous.
: I can find no origin for this use of 'lemon', although one source does indicate that this sense of the goes back to c1910 for 'something worthless'. The earliest use, mid C19, is for 'a person of sour disposition'. This use is clear.
: Any help with the c1910 version?

Here's the entry from Eric Partridge, "A Dictionary of Catch Phrases British and American":
A derisive reply to a query–or a request–needing a 'yes' or a 'no' but hoping for 'yes'; a 'sarcastic remark–acidic in its conclusion', as Noble aptly calls it; orig. (c. 1910) US–cf the US slang "lemon," used since c. 1900, for 'a sharp verbal thrust, criticism, or retort' (Wentworth & Flexner, "A Dictionary of American Slang"); adopted in England c. 1919. Its origin lies either in a lemon's sourness or, according to legend, in an improper, indeed an exceedingly smutty, story circulating during the 1920s. In Maurice Lincoln's novel "Oh! Definitely," 1933, occurs this illuminating dialogue:
'Written by some fellow with long hair who lives in Bloomsbury, I expect,' said Horace.
'Why?' said Peter.
'Why what?'
'Well, why would he have long hair like that and live where you said?'
'The answer's a lemon,' said Horace.
In the US, the thought is expressed a little differently. In 1974, my loyal old friend W.J.B. wrote me thus:
In the US we have a phrase "I drew a lemon" or "It turned out to be a lemon," etc. If we buy a new car which has 'bugs' in it, isn't working properly, we say, "It's a lemon."
For years we have had slot machines in gambling joints. You put in a coin, pull a lever, and a row of the conventional objects appear on the face of the machine, bells, plums, etc. If you get a whole row of the same objects, all balls, say, you win, and out drops a handful of coins. . . . you may draw a whole row of yellow LEMONS, and YOU GET NOTHING. Lemons mean a bust, a disappointment. Hence, when someone says "I drew a lemon," the slot machine connotation is well understood.
But Shipley, 1977, suggests that it prob. derives from a very popular song, c. 1905, with its last lines of the chorus:
'But I picked a lemon in the garden of love,
Where they say only peaches grow.'