Thread: Fuel usage S3 2.6 10MPG!!

Originally Posted by PhilipA

The fixed needle Strombergs will wear the needle and main jet over time. I am a bit confused whether you are talking the early Stromberg with fixed needle and movable main jet or the later with movable sprung needle and fixed jet.

I had a RRC in Saudi that would not meet the ADAC roadworthy until I replaced the needles and jets in both carbs.
I suggest that you fit new needle and main jet as a first action.

Regards Philip A

Hi Philip,
It is a fixed jet and fixed needle (apart from the retaining screw). Needle shoulder is flush with the bottom of the piston. Non tamper setup I think.
I checked both with a magnifying glass and made sure the needle was centered.
Couldn't see any wear, and the plugs are a nice light brown.
I have been running it at 3 deg static advance. I am going to set it at 10 as several posters have suggested and see what that does.
Given the low-ish compressions and the fact that most use is 1st & 2nd gear I think 5km/litre is all I can reasonably expect.
Thanks for the suggestion.

Regards,
Terry

Ah - yes if you're not actually moving quickly and only using 1st and 2nd, then that's about right.

If you can, take it for a decent run on the road and see what the usage is in 4th at 80 to 90KPH - you'd be closer to 20MPG I would suggest.

It is a fixed jet and fixed needle (apart from the retaining screw).

Now it's quite probable that I am wrong, but AFAIK there are only two versions of Strombergs ( other than the US spec ones with auto choke)

One has a fixed needle held in by a screw and the main jet is adjusted from below where there are two concentric nuts/bolts on the bottom of the bowl to adjust the main jet up or down.

The other type with a sprung adjustable needle with a special tool ( which I have) has just a cast bump on the bottom of the bowl .

If you have the type with the fixed needle and adjustable main jet it is very possible it and the main jet have worn over time. This is the type I think you have seeing the age of the car.
Regards Philip A

Originally Posted by Homestar

Ah - yes if you're not actually moving quickly and only using 1st and 2nd, then that's about right.

If you can, take it for a decent run on the road and see what the usage is in 4th at 80 to 90KPH - you'd be closer to 20MPG I would suggest.

Hi Homestar.

20mpg would be great. Usage is mostly a run into town every 2 or so weeks (to fill up) then around the property moving stuff around. Only light throttle and slow speeds.
I probably should do trips down and back a couple of times to get the road consumption figure.
I will when I advance the timing a bit.

Cheers,
Terry

Originally Posted by PhilipA

Now it's quite probable that I am wrong, but AFAIK there are only two versions of Strombergs ( other than the US spec ones with auto choke)

One has a fixed needle held in by a screw and the main jet is adjusted from below where there are two concentric nuts/bolts on the bottom of the bowl to adjust the main jet up or down.

The other type with a sprung adjustable needle with a special tool ( which I have) has just a cast bump on the bottom of the bowl .

If you have the type with the fixed needle and adjustable main jet it is very possible it and the main jet have worn over time. This is the type I think you have seeing the age of the car.
Regards Philip A

Hi Phillip,

I think I have some strange mixed setup that the army might have fitted, Definitely no needle adjustment, although the needle is the correct 4J according to the manual. And the jet is held by an internal collar with no external access. Just the bump you describe. It is a 1980 ex army GS.

I reckon that if the carb was the problem the plugs would look like lumps of carbon, but they are brownish with just a slight film of oil on the outer electrode.

I am going to advance the spark timing first, I have been sticking to the w/s manual 3 deg. so we will see if 10 or 12 deg. improves things.

Cheers,

Terry

Originally Posted by rover-56

Hi Homestar.

20mpg would be great. Usage is mostly a run into town every 2 or so weeks (to fill up) then around the property moving stuff around. Only light throttle and slow speeds.
I probably should do trips down and back a couple of times to get the road consumption figure.
I will when I advance the timing a bit.

Cheers,
Terry

Fuel consumption will Always be Much higher in any vehicle regardless of type or age if it is mainly used to "Beetle" around the property and 10MPG is probably about right.
Next time you go to town to fill up fill a jerry can up as well then top up the tank when you get home and take note of the amount of fuel you have used on the way back from town.
Assuming that you are travelling at highway speeds in top gear on this run this should give you a more accurate calculation of your fuel consumption so that you can make the necessary adjustments based on this.

Have just set the base timing at 12deg. Engine seems quite happy, no pinging. Seems a bit more lively.
I will do another run into town next week and do a consumption check, and report the results.
Terry

A kilometer in first or second gear is a lot more rotations of the donk than one in top gear, so it's probably not as bad as you think.
Fill the tank up with some 98 octane and take it for a decent run on the tar.
A set of Cookies extractors will get it cracking too.
The six is a sweet motor when running well.

Cheers, Mick.