WEBER 32/36 REPAIR TIPS

[bertvorgon]

Possible the moderators could put this as a sticky?


I thought I would do this write up for those of us that still use the old reliable Weber 32/36 carb. This will be about how to repair some of the common wear that takes place, primarily the loose boost venturi scenario.

First thing to do is take the top of the carb off, and set it to the side, being careful to not rest it on the float, as that could bend the tang, and change your float level. Remove the old gasket, paying attention to the fact that it is the CORRECT one! There are two styles of gasket, and if you get the one with the small protrusion into the float area, you will have problems with fuel slosh. I reuse my gasket untill it looks really dark in colour, and just looks like it has no "crush" left in it. This gasket is critical for sealing, so that each circuit gets a perfect signal.

So, wiggle the booster venturi’s, and if you detect the slightest movement…time to STRIKE! You may want o do it anyhow, as a pre emptive maintenance. They will loosen up over time.
Now, what you are going to do is get a nice sharp set punch, or, even a good quality nail will do. As you can see in the picture, you are just going to “tap” the area I have shown, to dimple the metal. This deformation is what locks the booster venture into place. Why Weber never did something better is beyond me. Make sure you support the carb on a hard surface, so the force is really transmitted to the body. Also make sure the throttle mechanism is not touching the ground, as you could bend something. The primary mechanism hangs down below the bottom of the carb a tad. You are dimpling the side AWAY from the fuel passages, as you want to load or press the fuel passage as tightly to the body by the fuel wells.

Now once that is done, you are going to both lightly sand just along the interface, where the booster meets the body of the carb. And I mean lightly. You are just getting the crud off, and roughing the surface so the epoxy has a good bond. Then, in that same area, get a Q-tip, or whatever, and clean the surface with rubbing alcohol.

The idea now is that you will mix up some good old 5 minute epoxy, and with a tooth pick, small nail, whatever, roll a small amount onto the tool you are going to use. Then, apply that down the seam(s) of the booster venture, at the fuel well end. At the top of the carb, where the gasket would go over the seam, just lay a small drop along that and work it in. You only need a small amount, as hopefully the picture(s) show. If it starts to “run”, you have applied too much. Remember, you are only finishing the seal, so the booster venture gets the best signal possible, with no air dilution being sucked in.

Let cure over night, and check that the area where the gasket goes, does not have a bump there. If so, just carefully trim with a sharp razor blade.

I have done this mod to all my Weber’s, which go through hell, with temperature change, and some very corrosive fuel mixtures howling through there. I have NEVER had the epoxy come off my carbs, and the booster venturi’s have stayed tight for the life of the carb.

The other good repair, if the throttle shaft bushings are worn, is to put in those bearing kits! They are cheap, seal nicely, and make the throttle very smooth in operation. If the actual shaft is badly worn itself, then that is a real problem. Most of the time though, it is just the bushings.

Put in a NEW accelerator diaghram. We need as good a pump shot as possible from these carbs, and any delay or lack of volume, will help to cause the classic “bog” off the line.

Vibration is another issue with these things. The choke plate can get very loose, and sometimes the throttle plate screws will loosen. Double check that All are tight. IF…you change the bushings to the bearings, make sure you absolutely use LOCTITE SMALL SCREW THREAD LOCKER, when you put them back in.

I have heli-coiled the threads on the top cover hold down screws, usually caused by years of over tightening.

Check the base hold down bolt area, as they can get cracked, which will warp the base and cause throttle sticking. If this has happened, the carb is toast. I actually had mine finish cracking one year, at a Solo, and it had me flying across the course, with the throttle stuck wide open…MURHY AT HIS FINEST!

Thanks to OKFINE for getting us the link to the carb tuning. I will not get into that, as their base recommendations are a good starting point. After that, well, that is what tuning is all about.

http://dimequarterly.tierranet.com/arti ... uning.html

thanks to Jim Hilton at Overseas Auto, in Vancouver, for his pictures of the gaskets and bearing kit.

Good luck, if you have any questions, just ask.

[bertvorgon]

Another 2 angles of where to punch the 2 dimples into the carb body.

The last pictures shows the 2 dimples

[bertvorgon]

Her is another look at the dimples on my primary venturi. It was looser then the rest. I have had my boosters out for some carb modifications, over time, so you can see it was a bit more of a gap, so the booster venturi itself was dimpled also.

[bertvorgon]

The paper clip (which I used to apply the epoxy ) shows the seams which you will cover.

[bertvorgon]

This is my existing carb on the right, with the choke plate milled off. That is a stock 32/36 on the left.

Those are the nice little roller bearings for the throttle shafts

[gbean]

Very nice!

This should help lots of carbs get back to their top performance potential.

[wagoneer]

Intriguing , if I may humbly ask a few questions
Re: venturis loosening
What specifically are the symptoms of a loose venturi ?
Does this produce an obvious carburetor performance issue?
Is the seam apart of the problem?
Re: milled choke plate
Why was this done?

Thank you in advance of your reply,
Wagoneer


Wagoneer

[bertvorgon]

The booster venturi(s) will "wiggle" if loose.

It can affect performance, as it could pull air in.......it would be subtle, but, when going after every bit of tuning gain...it all helps.

The problem is the seam, or more basically, if they have loosened up over time, then that is where the air can be pulled in.

The milled choke plate was done in my very specific case to allow best air flow INSIDE my blow through turbo airbox setup, made more clearance from the top of the carb to the inside top of the air box. I have never needed a choke to start my engine.