Hi.
I also had trouble when trying to find the lyrics for this a couple of years ago. I first heard the song when I went camping (as a kid) with my family in Cornwall way back in the 1980s. One of the attendants on the campsite also did a folk duo thing and it was one of his songs that really stuck in my mind. I eventually tracked down these lyrics through someone I met on a concertina weekend.

OLD JOHNNY BUCKER.

G
Old Johnny Bucker he lived by himself,
G                       D
As long as he had perfect health.
D
Then one day he got himself a wife,
D                               G
To look after him for the rest of his life.
G       D                 G
I do believe, I do believe,
G                                    C
That old Jonnny Bucker was a gay old bucker,
        D                       G
And a gay old bucker was he.

Old Mrs Bucker she had a bad leg,
The doctor ordered her to bed.
Johhny came in, the doctor said to him,
"You'll have to rub your wife's left leg with gin.
I do believe, I do believe……

Old Johnny Bucker he thought it was a sin,
To rub his wife's left leg with gin.
So he poured the gin right down his throttle,
And rubbed his wife's left leg with gin.
I do believe, I do believe……

Old Johnny Bucker went walking one day,
Beside the river he happened for to stray,
He tripped and fell in then gave a shout,
But there was no bugger there to pull the bucker out.
I do believe, I do believe……

Now God made man and man made money,
God made bees and the bees made honey.
God made the devil and the devil made sin,
We'll have to dig a hole to put the bucker in.
I do believe, I do believe……

Old Johnny Bucker he went up to heaven,
He reached there about 10 past 7.
St Peter he met him at the gate,
He said "You'll have to go below because your 10 minutes late.
I do believe, I do believe……

Various sources including Bampton Morris, Ken from Trewan Hall, and Anne from the Kilve weekend.