Hmm - OK I got two different sizes

Yep, check out a post I just put up on the fuel tube O rings on the other GO forum, It's easy to do and very effective. Like I say, I have been running the same fuel tube O rings for just on a year now, no problems at all. I just didn't want to put the same flakey factory O rings back in, and Marks nitrile ones were not available at the time, so neccessity was the mother of invention