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?
From your ole' mate Jeff
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.
I'd rather wear a Beetle out by racing it than by polishing it!
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
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https://www.facebook.com/FlatFourStarting 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
Don't let body work get in the way of real suspension travel
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.
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OZ Towdster wrote: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
You could go for a drive with the fuel cap loose to check this one.
From your ole' mate Jeff
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.
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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.
beetleboyjeff wrote:OZ Towdster wrote: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
You could go for a drive with the fuel cap loose to check this one.
Or when you take it off there should be a real rush of air noise
Futue te ipsum!!!
Thanks for your ideas people, looks like another weekend in the garage with a brew and a bit of good music, could be worse.
