300 Revenge fill line backs up on occasion but not every time. Change the angle of the hose, no improvement. Some days no problem. Haven't checked the vent yet..just odd it is intermittent?

Seems like it would have to be a venting issue, odd that it would be intermittent though. I've never had any issues like that. I do hate how it spits out the vent when you fill to the very top though. It seems all boats do that though.

I have a device that suctions over the vent that catches the fuel...works good.

Post a pic were did you get it?

http://www.tgmmarine.com/nospills/pages/products.html

Works good, IMO.

Cool thanks.

Are these vents removable from the outside for cleaning?

That's definitely a venting issue. Had the same problem on a Mirage I owned years ago. I had the vent hose replaced and the problem disappeared.

Check your vent for spiders. I had it happen and after the third geisser pissed fuel all over me I unscrewed the vent cover and there were two white disks the spider had created on either side of himself within the vent tube. Removed and never an issue again.