Fuel consumption

[Carl1234]

Hey everyone. I need some advice. I recently drove my 1971 1300 TP (which was rebored by the previous owner to be 1600) down to cape town from Joburg. I tracked my distance and fuel usage the whole way down and I averaged about 9.5L/100km which isn't great but for a 52-year-old car, id find it acceptable (although I have heard that some people can get their bugs to do 7L/100km). This is where the problem started as I noticed my fuel consumption on the streets of CPT to be significantly higher ( between 15L -17L per 100kms) Now this is shocking. After following some advice on Facebook which recommended that I reset the carb as there is more O2 down at sea level therefore higher consumption. I thought this worked but alas today's fill-up yielded a whopping 18L/100kms. I have an after-market 34 pict 3 carb. What can I do? The only issue with my bug currently is the lack of an oil breather tube as I switched to a pancake filter, however, I am going to revert back to the classic oil type. What am I doing wrong? Should I get a proper mechanic to take a look at my timing and carb? I am 18 and rebuilt my engine so I still don't have the experience when it comes to timing. I also suspect there may be a vacuum leak. Would this cause increased consumption? How can I get more distance for my money? what are some common causes of increased fuel consumption?
P.s. I try my best to drive as economically as possible.

[sean]

Hi

I can tell you outright your biggest issue will be that Chinese aftermarket carburetor.

Your 1300 t/p would have had a 31PICT carb originally. The flange on the manifold is suited accordingly. Did you use an adapter flange to fit the 34PICT carb or did you change the entire manifold?

The 34PICT carbs are the worst. The Chinese ones come standard with incorrect jets and are renowned for over fueling.

Install an original Solex 31PICT back in your car and you will have solved 90% of your issues.

Vacuum leaks, incorrect timing etc will also have an effect on fuel consumption.

[73type2]

He mentioned that the engine is re-bored to 1600. In that case, wouldn’t a good Solex 34Pict3 help?

[Dawie]

One of the things to check would be that ignition advance is working correctly. Vacuum advance pipe connected to the correct port on carb. Confirm that the vacuum canister is not leaking by sucking on it's pipe.
In case you use the following:-
Aftermarket electric fuel pumps are known to cause over fueling, by forcing fuel past needle + seat, because of excessive pressure. (Most pumps available nowadays were intended for carbs which have a return line to tank).

Beetle odometers commonly develop a crack on one of the small gears which lives on a little shaft. Then it may partly slip for years before it eventually fails. So car registers less distance than it actually travels. After 30+ years his is common on many old VDO and some other speedometers used in various makes of old cars.

If you still have the short ratio transmission from the 1300, this will also hurt a bit.

[retrovan]

You probably have low profile tyres on the back too look kool.

This will drink fuel, with the 1300 gearbox.

Get yourself 15 inch rims and fit 165 by 80 tyres, or bigger.

This will not be a problem as you have 1600 cc now so you can take bigger wheels.

Get "Quick start" and spray around your carb and manifold with engine idling.

If engine revs pick up at a spot, thats where you have a vacuum leak.

Fuel cost more then tyres, so do yourself a favor.

Herman