Hi guys, first post, thanks in advance. This is seriously driving me mad. 73 Beetle runs well until on the freeway at 90/110 km, after about 10 mins will start to run rough, lose power and stop.Have replaced points,plugs,leads,condenser,dizzie and rotor. Carb off (several times) cleaned and reset,blew out fuel ilne ect.Someone suggested carb icing and I found rusted out riser so replaced that with ill fitting Brazilian rubbish. It ran well for about 200km on our backroads but on NYE, back on the freeway and same same aarrgh. Any ideas ? Dual port 1600 is in good condition, has pod style air filter.

Dodgy fuel pump?

Many years ago, I had an almost identical problem with my 1961 Beetle. After going through similar dramas to yours, I finally found the problem......the 'curly' hose from the fuel tap to the steel fuel line had a kink in it, and was restricting the fuel flow. All it needed was a twist, and problem solved. Hope yours is that easily fixed.

Thanks Greg, yep replaced all fuel hose too

not blocked in the tank end,just sounds like its running out of fuel or like Jeff suggested dodgy fuel pump

Starting to think about the fuel pump again, anyway to test em apart from turning the engine over and watch it spray everywhere?

Also check the fuel tank breather hose , as if this is blocked then it will only get worse on a long trip when it doesn't get a brake for the fuel tank to go back to a neutral pressure instead of the possible negative pressure it is becomming with a blocked breather hose which once the negative pressure gets to great the pump can't draw the fuel

Fuel pump pressure and flow rate spec in a good manual.
Also fuel pump pushrod length and my favorite, foreign matter behind the needle and seat, remove it from the carb lid to check all is clean behind the brass body of the needle/seat.

it could be a coil if its dodgey what you describe would happen after a small drive than over heat and stop when its cooleds down away ya go until etc.etc.

Coil is possible, and another thing that gives very similar symptoms is the ballast resistor (if you're running one).
If you meter the ballast, it will look fine, but after a few minutes running, the resistive filament gets hot and opens up (open cct), simulating a really uncool rev-limiter. When you stop the car to look, it's cooled off and connected again.
If you have a ballast and it has the slightest rattle, replace it.

Thanks for your ideas people, looks like another weekend in the garage with a brew and a bit of good music, could be worse.