Solex Carburetor Tips

The Solex carburetor is manufactured in India and is original equipment on some Jeeps built by Mahindra and other overseas licencees, including Hotchkiss in France. It is also offered by parts dealers in North America as a replacement for the Carter carb originally found on Willys Jeeps.

EngineThe Solex is now found in many CJ-3Bs, including a 1999 installation in Rolfe French's '61 (right). The relative advantages of the two carbs was a perennial topic for discussion on the old CJ-3B Bulletin Board, and there were some specific complaints and suggestions:

Accelerating Pump Adjustment

Jax: "Just got a Solex for my '55 3B and so far the hook up is going O.K. I've avoided a few glitches thanks to the info, advice, and posts in the tech section, very helpful and much appreciated. I have a few questions on the accelerating pump assembly, control rod and its adjustment. As it came out of the box the adjusting and lock nut were all the way out at the end of the rod threads.This rod adjustment with the spring controls how far in and out the lever on the accelerating pump goes with the action of the throttle lever. As it is,with the nuts all the way at the end, the threads move in and out of the connecting hole in the throttle lever assembly and the lever on the accelerating pump has limited travel. I'm thinking that can't be right? Screwed further down the action on the rod and pump lever travels much futher in and out but how far to go? How does this affect the accelerating pump and carb performance?"

Glenn Smith: "They come from the factory pre-adjusted and should be fine. Actually, I believe the instructions say not to adjust anything other than the idle. All I can say is mine was fine out of the box, all I did was set the idle. Personally I think you should set it back where it was and try that."

Solex carbs don't like going uphill!

Brandon: "I am having a tough time finding the correct float level for my Solex carb. I have found other info, but not that specific. The 3B, when faced uphill, will have a devil of a time starting, and when it does it will cough and sputter for a minute till it smoothes out, and the exhaust smells like gas. I assume it is a float problem. Any help?"

Austin had the solution: "If your Solex is the same as mine it has a vent hole in the top cover that vents internally not too far from the throat of the carb. When your Jeep is facing steep uphill, fuel can run through the vent hole into the carb throat and flood it or at least make it run really rich. I put a plug in my vent hole and drilled a hole in the top cover of the carb and vented it externally. Now the Jeep runs a lot better on strange angles.

Fuel Pressure Regulator

Dan Fedorko asked: "I just got a new Solex carburetor for my 3B. The instructions that came with it suggest using an inline fuel pressure regulator. Is this really necessary?"

Reed Cary: "This gives rise to thoughts, though perhaps undue. I have had problems with my Solex (on an L-134) since I installed it. But I don't think they are fuel input pressure related. The fuel reaches the carburetor OK, and I even recall checking out my fuel pump output pressure, which also seemed OK. So a regulator seems uncalled for. What I experience is two- or three-fold: 1) The Solex runs too rich. I notice this on the plugs, when pulling them, and in gas mileage! I also notice this at higher elevations - just no gusto. 2) I have had the problem which resembles vapor lock: in warm weather, when I have been driving at highway speed (50mph) for a time then stop, it is really hard to fire up again. I have to wait for things to cool down, it seems. 3) When the jeep stands for 2 days or more, the carburetor reservoir seems to be drained. (It is like trying to start when one has run out of gas.) Aparently, the #s 2 & 3 are related. There is some sort of "down syphoning" going on, perhaps a carburetor boil-over despite the thick gasket beneath the carb base. I supply all this perhaps extraneous information, because it might be related.

Christophe Guizard's solution: "I have the same problem in my Jeep (French M201 model) if it stays a long time without running. One thing to do is to inject directly inside the carb a little quantity of gasoline, the Jeep will start at the first requirement. Probably stop a little time after, but will restart rapidly. After that no problem!"

Factory Information

Any further user comments on the above questions are welcome. Below are some parts lists and adjustment guidelines from manufacturer Pentafour Products Ltd.

Rick Cool bought a Solex M34PBIC, recommended for the Willys civilian F-head, and forwarded a copy of the technical bulletin included with it. See the four pages (50K GIF files):


Andy Carter's Military Jeep Page published a couple of Solex carburetor technical information sheets which refer to the slightly different M32PBIC.See the complete M32PIC parts list (60K GIF) and the manufacturer's instructions on installation and adjustment (60K GIF).

Christophe Guizard in France sent an exploded view of the 32PBIC. He says, "This one has an automatic starter, not used on the French Jeep." Christophe also sent a scan of a page from what he says is a "very good article on Solex 32PBIC restoration (160K JPEG) in the January 2002 French magazine GAZOLINE. Fully illustrated step by step restoration (in French but lots of pictures.)"

32 PICB See some general comments on the Solex Replacement Carburetor on CJ3B.info.

Elsewhere on the web, see Solex: Selection and Tuning of the Carburetor, a complete manual published by the Arnolt Corp. of Warsaw, Indiana.

Thanks to all the contributors, and to Tech Editor Andy Stock. -- Derek Redmond

See also CJ-3B Tech Tips on the original Carter YF Carburetor, and a Weber carb installation in an F-head Performance Enhancement.

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Last updated 17 June 2009 by Derek Redmond redmond@cj3b.info
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