Carter vs Solex gas mileage.

[Go Joe]

I have a question for anyone with the F-head engine who has had both the Carter and the Solex carburetor. Did you notice much of a difference in gas mileage between the two?

Thanks

[gmwillys]

Go Joe,

I just know what I've read on the subject. The original Carter carburetor tend to be a lot more reliable. The Solex tends to be troublesome to get just right. A common upgrade is to use a Webber carburetor, but I don't have too much information about any troubles seen from the upgrade. A good source of everything carb related is the following;

http://oldjeepcarbs.freeforums.net/

[Go Joe]

Go Joe,

I just know what I've read on the subject. The original Carter carburetor tend to be a lot more reliable. The Solex tends to be troublesome to get just right. A common upgrade is to use a Webber carburetor, but I don't have too much information about any troubles seen from the upgrade. A good source of everything carb related is the following;

http://oldjeepcarbs.freeforums.net/

I bought this old Jeep 3 years ago and the original carb leaked real bad. I've rebuilt lots of carbs but this one is over 60 years old and the new Solex was so cheap, I just bought it. It runs ok but gets horrible gas mileage. It's less than 10 mpg and a lot worse when I use the choke.

[gmwillys]

LarrBeard had touched on the subject before, where it has been necessary to run a fuel regulator between the fuel pump and the carburetor to restrict the fuel pressure.

I did find some information in regards to the Solex carbs in Jeeps;

https://forums.g503.com/viewtopic.php?t=92437

https://www.thecj2apage.com/forums/new-solex-carb-does-anyone-have-success-with-one_topic34861.html

[Go Joe]

I think I'll try a regulator. I just have a cheap $50.00 electric fuel pump on it. It's not high performance at all but it still could be too much.

[gmwillys]

Whether the carb is a Carter or a soles, they all only require 2.5 psi for proper operation. Most electric pumps put out 5 to 8 psi. You'll have to play with the air/fuel mixture to get it back to where you need to be, but you have not had any issues with performance outside of poor milage. You are already ahead of the curve. Keep us advised of your progress.

[Go Joe]

I live in a small town. I may have to order one.

[gmwillys]

CARQUEST or O'Reilly auto parts should get you one fairly quickly.

[LarrBeard]

I live in a small town. I may have to order one.

https://www.oreillyauto.com/detail/b/mr--gasket-4367/performance-16477/fuel-system-16571/fuel-pressure-regulators-17798/2c0511bdf1f4/mr-gasket-fuel-pressure-regulator/9710/4514726

Mr. Gasket # 9710. My F-134 runs very nicely with a Carter YF and about 1 1/2 PSI of inlet fuel pressure. That's as much fuel as it needs and the float and needle handle it very nicely.

[Go Joe]

https://www.oreillyauto.com/detail/b/mr--gasket-4367/performance-16477/fuel-system-16571/fuel-pressure-regulators-17798/2c0511bdf1f4/mr-gasket-fuel-pressure-regulator/9710/4514726

Mr. Gasket # 9710. My F-134 runs very nicely with a Carter YF and about 1 1/2 PSI of inlet fuel pressure. That's as much fuel as it needs and the float and needle handle it very nicely.

That's what I put on, that's where I got it and that's what it's set at. It run beautifully but it didn't run bad before. Now I'll just have to see how much my gas mileage improves. I don't know why I didn't think of that. I've had pressure regulators on vehicles before, like 40 years ago. When I put this carb on, I read that it only needed 1 1/2 to 2 psi. I didn't think that cheap electric fuel pump put out that much. I tested it and it puts out 5 1/2 psi. Thanks for your help.

[Sebastian21]

I am replacing my solex with a carter YF. The solex floods very easy and floods out while driving. I have had a lot of trouble adjusting the solex with that piston choke. I have had carter on my other Jeep and it worked much better.

[LarrBeard]

[QUOTE=Go Joe;6078]That's what I put on, that's where I got it and that's what it's set at. I didn't think that cheap electric fuel pump put out that much. I tested it and it puts out 5 1/2 psi. /QUOTE]

Let's hope that fixes things. I didn't think a rebuilt Jeep pump would put out over 8 PSI either, but wow!, was I wrong.

If that doesn't fix things, we'll guess something else.

[Go Joe]

I took the old girl on a 36 mile round trip this afternoon. That's the farthest its been in decades, maybe ever. It did just fine.

[gmwillys]

Good deal. Did your millage improve?

[Go Joe]

I don't know yet. It still seemed like it took quite a bit but it only has a 10 gallon tank. I filled it up when I got back and wrote down the miles. I'll calculate my mileage the next time I fill up. It definitely runs better.

[gmwillys]

I posted this on another question regarding the carburetor debate.

One thing I didn't think about, was the heat riser vane in the intake manifold. The guy that runs the old Jeep carb website posted this;


.
Post by scoutpilot on 3 hours ago

Without a properly functioning heat riser valve, going after the carburetor will frustrate the living heck out of you. If the valve is stuck in the open (cold) position, heat from the exhaust will continuously bathe the bottom of any carb you put up there. The heat will cause the gas in the bowl to boil. The resulting pressure will force fuel past any metering device and flood the manifold.

[Go Joe]

My old 1956 Jeep doesn't have a heat riser. I'll be buying gas in a couple days and I'll calculate the mileage.

[Go Joe]

I bought gas just now. I got 13.4 mpg. I was hoping it would be a little better than that.

[Sebastian21]

That is excellent milage. I have had a lot of jeeps and my milage was between 9 and 11.

[LarrBeard]

I bought gas just now. I got 13.4 mpg. I was hoping it would be a little better than that.

That's not bad. The F-134 in the 3200-pound truck gets about 12 mpg, depending on hills and headwind.

[Go Joe]

Ok, thanks. It is geared pretty low too.

[gmwillys]

Most likely you have a 5.38 gear. A 4.88 would help, but there is a gear set available for a 3.54. You may would want to check into an overdrive unit. Then you would #1 keep the RPM down for increased engine life. #2 increased highway Sprint speed. #3 an increase in MPG at cruising speed.

[Go Joe]

That would work but I've already spent a ton of money on this Jeep. Mechanically, it's as good as anyone can make it. I need to drive it now. What it really needs is a new body. I don't think I'm going to be able to afford that.

[gmwillys]

The Jeep doesn't have to be pretty, just as long as it gets you to where you want to go. In my opinion, I would not invest in a reproduction steel body, but I would purchase American made replacement panels. A piece here and there, then eventually you'll have what you need. I stripped the paint off of our 2A, thinking that it was a complete Illinois rust pile. After chewing through six layers of paint, and a half inch of body filler, the body wasn't as bad as I thought. There are some panels that have been brazed in, so it gave it a look that is unique. I'm going to keep the bare metal look for a while, or at least until I gather all the steel to replace the floors and side panels.

[Go Joe]

My Jeep is an old farm Jeep from Iowa. It is extremely rusted. There is no solid metal. The underside is especially bad. It didn't even set level on the frame when I bought it. I ran a piece of channel iron under it behind the seats to level it on the frame. Previous owners have fixed the body several times and repainted it several times. I was probably foolish to buy it. I traded a shotgun and $100 for it and it barely worth that. I have over $4000 in it now. (Mostly from KaiserWillys) It had good tires, a very good motor and a good drive train but that was all it had going for it.

The wiring was rotten so previous owner cut out all the wires everywhere and stripped everything behind the dash but the speedometer. Then he realized he didn't know how to rewire it. That is what I do best. It had a plastic gas tank out of a boat. The radiator leaked, the water pump leaked, all the hoses were rotten. I replaced the entire brake system. The springs and shock were bad. The ring gear on the flywheel was bad. I keep a log on all of my vehicles and I have a long list of parts I've replaced. But it has 140 to 145 psi compression. That's more than it had new. I runs and drives great. I use Mobil 1 motor oil in it.

So far I have paid cash for everything. I won't buy a body until I can pay cash for that. I'm retired now and that probably won't happen. My grandson has his eye on it. He may be the one to replace the body. I'm done some research into it but I haven't made any decision3211321232133214

[Go Joe]

It will only let me post a few pictures. Here is what it looks like now. https://www.facebook.com/joel.merrill.3/media_set?set=a.10213793565366007&type=3