Green tanks compatibility question

[mark 55]

I often see green gas tanks for sale, at swap meets,etc Many sellers say they will fit a number of motors but I am hesitant to believe it. I am not very familiar with the design differences (small vs large gas caps, etc) and am finding it hard to determine fit. For example: will ke4 tanks fit kg4 models? How about ke7/kf7/kg7/kh7? Are they all interchangeable?

Also, regarding the gas caps, I purchased a gas cap that was supposed to fit my kg4 (mine had a huge cork in it when purchased) but alas it was too small. It was a green one with a "k" on it. I started thinking maybe the tank on the motor is not correct and maybe came off a ke7 or something.

Any help/insight appreciated!
Thanks!
Scott

[dave bernard]

3 size tanks

1 mark 5 SMALL
2 mark 7 ke4 MEDIUM
3 20 cube k models and kg4. LARGE

EARLIER HAD SMALL CAPS WITH SMALL FILTER.
LATER HAD LARGER CAPS WITH THE HEX FILTER.