kleky

71 44bhp bug, no engine mods. Drives for about 20mins then eventually starts holding back like the power just went. Keeping the engine alive like this is hard and will cut out if I dont keep enough revs. Once it cuts out I have to wait until cool.

Thermostat, fan, carb, basically the cooling system has been checked and is ok. Looking at the fuel filter, it doesn't seem that full so checked the pump and thats ok. I put the filter on the line feeding into the pump and it was even worse (did it even sooner), so I quickly put it back. Due to this im inclined to think its fuel starvation, but ran out of options

Any help would be great!!!

Thanks
Ian

Doug Rodrigues

If I remember correctly, my '68 Bug was 65 hp. Your '71 should be at least that same hp. Anyway, how is the valve adjustment? Intakes and exhaust should both be adjusted cold (able to not say OUCH when you hold your hand on the cylinders) to .006". How is the timing? Is the dwell angle close to 45 degrees OR points set at .018"? Did you actually see the thermostat move to the open position as the engine warmed-up? Are the heater tubes connecting the fan shroud to the heater exchangers in good shape or are they leaking air pressure? Is your Bug used for the street or for off-road? If off-road, try taping closed the fan shroud duct outlets for the heaters: You get more cooling air pressure that way. Duct tape would do the job well.

The fuel filter never looks filled...that's normal. Maybe you could check the fuel pressure? Got a gauge to stick on the pressure line to the carburetor? Off the top of my head I think that your valves may be a bit on the tight side. Better to run a little loose than too tight. Could be anything. You'll just have to go throught the process of elimination starting with what is covered during a tune-up.

kleky

Cheers for your help, I appreciate it.

Its a lot better than it was now thanks. I put the timing right, changed the plugs and leads, and found a very small crack in the fuel pipe causing it leak and probably lose pressure.

It drove at the weekend quite far, about 75 miles, stopping and starting a few time too. Got back home, went to the gym, tried to go home and no spark. Fidled about for a bit and it started fine. Im thinking the distributor might be playing up but its quite new looking.

Anyway, while it sits idle it eventually goes lumpy and cuts out. This was after a long journey though. Im hoping this is a common beetle problem?

Doug Rodrigues

Idles and then slowly runs worse and then dies? Almost sounds like a carburetor problem. Does the idle adjustment mixture screw function as designed, i.e. proper idle with the mixtue screw turned toward rich 1 1/2 to 2 turns? If the idle doesn't seem to properly smooth with the mixture screw, then the carburetor probably needs cleaning by soaking it in a cleaning solution. A gallon can of such cleaner, with the parts basket can be purchased at most auto supply shops. You'll need to soak that carburetor for at least a few hours...disassembled, of course. If you don't have an aircompressor to blow out the ports of the carb after rincing, you can go to Radio Shack and buy a can of "Velocity dust remover spray" to do the same thing.

kleky

All sorted!!

Carb was fine. It turns out that my rotor arm was faulty. When hot it was passing no current. As soon as I replaced it, it worked a dream, super smooth, a real chugger

Thanks for your help guys!!