Steve;

That the choke pulls back in is actually the unusual condition...there is no provision for keeping it pulled out and the chokes engaged against the return springs at the carbs, other than the friction in the cables...so if the friction in these is so low that the return springs on the carbs are enough to overpower the friction, I suspect you have everything well lubed and there's nothing wrong with that! Generally the choke pulls back a bit but does stay engaged...and you really don't want (or need) it out fully for very long anyway...seconds are enough really...I wouldn't let it bother me really, but you could always but a quarter between the control and dash...and after ten seconds, a nickel...and after ten more seconds, a dime...

Cheers

Shannon; TNX for reference!