TheSamba.com :: View topic - 67 beetle 1600cc dual kadrons after 15mins car loses power

Fri Mar 30, 2012 7:58 pm

after driving for 15 mins or so the car backfires and loses power. runs great for the first 15 mins. had the carbs synced and adjusted left shop and same thing happened. the next day ran fine and once again after 15mins runs like crap. anyone know a cure to my problem? i just bought car a few weeks ago

Fri Mar 30, 2012 8:23 pm

Sounds like it could be electrical. I'd check either the coil or condensor.

Fri Mar 30, 2012 8:46 pm

ill check it out i was thinking it was running to rich and soaking the plugs i didnt think about the electric

Fri Mar 30, 2012 11:18 pm

Na if it was soaking the plugs with gas it would foul them and wouldn't run good at all. You said it runs for about 15 minutes then craps out, let cool then runs again for another 15 minutes.
Electrical parts like coils, relays, condensors, ect., can act funny when they get heated. They can shut off, stick, or go out, then cool down and be fine.
It's just a suggestion, but i'd start there.

Sat Mar 31, 2012 4:15 am

Electric fuel pump?

Sat Mar 31, 2012 4:19 am

Fuel pressure is what? If you have a gauge, I'put it on and run the car a bit - pressure could be to high or too low - or your volume is too low and you are running out of gas.

Mon Apr 02, 2012 8:56 am

I think it may be getting to much fuel. Thinking I might get rude of the dual carbs and go with a single.

Mon Apr 02, 2012 10:09 am

It's not a "too rich" problem. If it was, it would foul the plugs and would run like crap all the time.
They just don't dry out and then run fine later. If they foul, their done.

Mon Apr 02, 2012 10:16 am

I would start on the electrical side of it. I've had coils do that before, would run find until car got hot. Then it would skip and act like the timing was off. Make sure you get a good coil with internal resistor.

Mon Apr 02, 2012 11:46 am

Pull off the gas cap, does more air than typical enter? Maybe you have a fuel tank vent problem.

I had this happen once.

Mon Apr 02, 2012 7:51 pm

Choke element not adjusted properly and closing the throat of the carb??

Tue Apr 10, 2012 1:06 pm

There's no chokes in these carbs, when I bought the car and drove it home the muffler filled with fuel and was glowing. Flame shot out of the exhaust. I got the carbs adjusted and that hasn't happened since but still have the loss of power and backfire. I did have a cracked distributer cap and got a new one. Going for a ride maybe that's my problem

Tue Apr 10, 2012 7:20 pm

Intake manifold leak at the joint where either manifold is bolted to the head? Engine runs fine when cold (rich mixture), then as engine warms up, the excess air leaking in at the manifold joint leans out that side of the engine, allowing the engine to still run on the 2 cylinders fed by the other Kadron carb.

When your engine is running a few minutes, check the manifold joints on each side by aiming a shot of brake cleaner spray at the base of the manifold. If the joint is not solid due to a slightly tilted manifold connection, the engine speed will increase noticeably almost immediately. Shut the engine off, disconnect your carb linkage at that side, loosen the manifold nuts to the head, rock the assembly slightly while pushing down; then tighten. You might even want to pull the entire manifold+carb off on that side to make certain there is not a small obstruction between the bottom of the manifold and the head joint which could prevent the manifold from sitting fully down.

Then you may have to adjust your carb linkage slightly again (ball socket end at the carb throttle arm on the carb/manifold you just retightened).

Wed Apr 11, 2012 2:42 pm

if you let it cool 10-15 minutes, does it start up and run again?
Runs for a few more minutes and dies? Repeating cycle?

If so... I would focus on the condensor. This is a common problem when they go bad as they get hot require to cool before working again. Pop a new one in and see if it improves before getting too involved in troubleshooting.

Wed Apr 25, 2012 4:43 pm

thanks for the help everyone, the car is burning way to much fuel to the tune of 10mpg i took it to a shop hopefully the can figure it out