it seems to me lot of fuel per mile = 8,9 miles per gallon

My 1988 2.5 liter (four-cylinder) YJ gets no better than 16-17mpg highway. With backroads and short trips, it's about 14mpg. Less than that if doing trails...

The "Jeep" package is inherently low milage.

 

Allan,

On my 66 CJ5 with F134 and a Solex carb... in town driving (short stop and go) with my timing not adjusted properly I was getting 12 mi/gal. On a mix of out of town + in town trip + my timing and my valve adjusted I am now getting between 16-17 mi/g. There are no significant hills in my area. I know I'm safe up to 100 mile on the odometer without a re-fuel not sure after that since I never pushed the limit and my fuel gauge does not work.

I can get you better numbers once I type in my summer log in my spreadsheet.

Pierre

 

Could be though because I have my timing set by vacuum gauge to as high a reading as it will give me at idle. The higher your VG reading the better your gas mileage.
Was the same way with my '66 Olds Dynamic 88 with the 425 in it. Timed to the specs in the books it got 9 miles to the gallon on the highway. Timed to the high reading on the Vac gauge, and it got close to 20 mpg.

My jeep came to me without any timing marks at all, which is why I used the Vac gauge to set timing.

 

I understand that I can change some parameters on the carb. It reminds me that long ago we were changing the "gicleurs" (bronze parts with a hole, to send the fuel inside the carb chamber) if bigger hole more power88??
A carburetor is a very complex invention, I have some difficulties to understand. It is very clever, subtle and to modify a parameter is not easy.
Moreover with the ignition which is complex too, I maybe could visit a specialist!
I have nearby a Caterham specialist, they also work on old cars like a Maserati or Lamborghini ... but they want $$$. reasonably because we are not in Paris but in a small city. Maybe it is a solution, the day when I get my monthly pension.

 

Cool I am going to look into that 1960 - I am just putting the engine back in tomorrow I might tune and try to get the timing advanced when I do and check it out

 

Bob:
when it gets warm (the engine) after you set your timing, try shutting down and restarting. If the engine starts right up you are golden. If the engine acts like you need a new battery, then retard the timing a tad. Just enough so the engine speed picks up again. Then tighten all hold-downs.

 

Be aware though, that this works with engines that do not run on computers.
Try this at your own risk, too. Just because it works for me, doesn't mean it will work for you.
One of the reasons I have the JEEP, is it is fairly simple to work on.

 

Read this first:

http://classicinlines.com/vacuum.asp

and this:

https://www.centuryperformance.com/forum/showthread.php/42-Engine-Tuning-Using-a-Vacuum-Gauge

 

Because any woman will tell you there is no substitute for cubic inches!

 

I would like to help our comrade out but I have no experience with Solex units. I agree that your not going to get great mileage with lots of stop and go but do think he could be doing a little better.

I hope I am not breaking any forum rules with the following offer ( moderators please let me know or delete if needed )

I do not have any YF cores for rebuild save my own spares, If interested members can help scrounge around and come up with a YF938 carb and ship it to me I will go through it complete with a viton tipped fuel valve and supply a set of new custom metering rods and a few spare parts and ship it to him PRO BONO.

What say yee fellow jeepers

 

*applause*

 

Thanks for help. I believe that I have to make some more tests. But I use only my Jeep for short travels. And now it will stay calm because bad season is coming, she waits in the barn. I am very sorry, but I have nowhere to go! And it is good with hot weather, but for health reasons I have difficulties to use the Jeep in winter. I must put back the hard-top and doors.
But I need also the Jeep for gardening, I have some trees to cut, I need it inside the garden ...with no hard-top for the work.
And now I am back in Paris, so it will be later.
The Jeep is fun in hot weather, of course in snow can be funny with a good top and heater but I am a little bit old for this pleasure.
Maybe...maybe one day, with one of my big boys, I'll make a trip to south of France. This is why I bought it, in souvenir of my adventures with a Willys on the Côte d'Azur, Saint-Tropez, Marseilles and area, long ago. Dreams are my reality...

 

I do agree with glen on further testing of highway mileage, if it ever becomes necessary and we scratch up a core I am good for it.