Name of a japanese song from around 1980

Hello,
my mother is looking for a Japanese song which she heard when she was little. Supposedly it was a great hit at the time (around 1980 give or take 2 years) as they also played it on the radio here in Slovakia. It was sung by either a little boy or a lady, it had a happy simple melody, almost like a children´s song. She also remembers some lyrics phonetically, but I don´t speak Japanese, so it sounded something like this to her:
Yama de ti sen ki no
somu komu
konogola tsukoti
hen yoooo
tota no ga neeeee
I know it doesn´t make sense probably... but please if you know the name of this song could you help me?

If you have a smart device, there are two apps that might help you, Shazam or SoundHound. For both you can just hum the melody and it tries to match the song. I don't know how well it matches older songs, especially one from Japan, but it matches more recent Japanese songs just fine.

It is Yamaguchi san chi no tsutomu kun.
(山口さんちのツトムくん）
http://youtu.be/ywSuNslWgbs

Yamaguchi san chi no tsutomu kun
konogoro sukoshi hen yo
do-shitano kana?

Because I am the same age as Kozue Saito(singer),When I was a child, I was listening.

Thank you so much haro1210, it is the song, we are very grateful :)