I experienced fuel line problems in my new 425 in the July-August heat. The engine bay was hot enough to soften the clear plastic tubing, causing it to sag tremendously. The sagging line was chafing against all manner of hard parts in the tub, and it was just a matter of time before it would leak. A bigger part of the immediate problem was that the fuel in the line vaorized virtually completely, resulting in a classic vapor lock stalling. Only after the engine cooled off and the fuel re-condensed, could it be restarted. I spoke with Terry about it and also had a good dialog with pairodime. Using a tire pyrometer, I measured ambient temps well over 200 degrees in the bay around the fuel line. When I mentioned that to Terry, he indicated that they would consider going back to conventional fuel line.
My solution was to change the line from the clear plastic (which BTW is not gasoline rated), to standard thick-wall, cord reinforced, fuel-vapor line which I picked up at my local auto parts store. I also re-positioned the in-line fuel filter forward of the firewall which separates the exhaust manifold from the battery. I then shrouded the entire fuel line with racer's heat shoud tubing
[HERE]. This is a fiberglass material bonded to an aluminum fabric. It's available as a tube, or as a (slightly more expensive) velcro closure. The tube version is applied by disconnecting the fuel lineand sliding the shield over it and then reconnecting. The velcro version is applied w/o disconnecting the fuel line, and is large enough to cover an in-line fue filter as well. I bought the shroud from Summit Racing
[HERE] Good folks, prompt service, and discounted price. Problem was solved completely. The shroud also absorbs any chafing, protecting the line itself
Without veering too far off the thread topic, I also managed to get better control in general of the heat in the engine bay using racer's 'floor and tunnel' heat shield, 'cool tape' and 'exhaust/header wrap'. What a difference it made. If anyone is interested, pls send PM and I'll be happy to provide details.