Carburetor rebuild question

[exp2000]

After eliminating fuel and fuel pump as a source of the problem, I ordered carburetor rebuild kits. I have a question about the main nozzle and idle tube. In the book the picture shows that the top of the main nozzle is higher that the idle tube, but in all three carbs, it is lower. How deep should the main nozzle actually be? And is there a special tool for taking the main nozzle out, as the way it is right now I cannot take it out. Please help.

 

[pnwboat]

Re: Carburetor rebuild question

Unless you see any problems with the main nozzle and idle tube, I wouldn't touch them. Seen many carburetors ruined by individuals attempting to remove the idle tube. The idle tube is very thin brass and is easily damaged. Finding a factory replacement is difficult. If you can find small brass tubing the same diameter, it will work as a replacement. Just use some carburetor cleaner and compressed air to clean out the passages.

 

[snake91876]

Re: Carburetor rebuild question

I took some apart today and mine are the same way as yours i think the are supposed to be and i know of no way to remove the tube.

 

[Frank Acampora]

Re: Carburetor rebuild question

As PNW said: If they don't have a problem, don't remove them. That said, the diagram is correct: the main nozzle only protrudes a little less than halfway into the venturi. It screws out and yes there is a special screwdriver with a notch in the center of the blade to remove it. screw it back in until it stops.

The idle tube is swaged into the top of the carb and then capped with the small plug.you drill and remove the small plug with a screw, then drive out the idle tube. However, replacing it is another story and a bit difficult to get it correct.
If it is plugged, a small length of 1/32 welding wire can be run through it. Lacking that a fine pipe cleaner can do. Spray everything with WD 40 until it runs freely from all holes. Do not use wire to clean the metered holes at the top inside of the carb.

 

[exp2000]

Re: Carburetor rebuild question

I created a tool from the old screwdriver. Removed the main nozzle and cleaned inside of the carburetor. I used B-12 Chemtool to clean. Is that OK?
Also, looking at the opening where the main jet goes, I can see the idle tube half way up, above the main nozzle and completely opposite from what the image is showing. All three carbs are like that.

Also, looking at the canal where intermediate air jet goes, should the idle tube be visible. In other words, does the idle tube goes all the way to the plug, or stops at the top of intermediate air jet canal?

 

[Frank Acampora]

Re: Carburetor rebuild question

The idle tube supplies gas to the hole or holes right above the butterfly. so, no, the tube does not go all the way to the plug. There must be space for fuel to flow. This is the low speed circuit and is controlled by the brass needle either in front or at an angle on the top side of the carb.

Messing with carbs is a good way to require a costly rebuild of these engines. When setting the carbs after cleaning them, read the FAQ sticky at the top of the page: Synchronizing carbs and timing.

I don't know B12 Chemclean but almost no solvent will harm the casting and brass parts. SOME solvents will dissolve the sealer used on the big welsh plug at the top rear of the carb.

 

[exp2000]

Re: Carburetor rebuild question

Thanks guys for help, I cleaned them with B12 and compressed air. Looks like I got a 1tsp of watter from crevices or the bottom one. Got a lot of particles out too, alomst like sand. Replaced all needles. Will complete assembly tomorrow and we will see if it stays on. Prior to this, it would work for 15 sec and than die and than I could not get it going again.

 

[jason32038]

Re: Carburetor rebuild question

Awesome job on the restoration so far.

 

[sidenberg]

Re: Carburetor rebuild question

Careful with the B-12. It will destroy any rubber on the needle and seat parts. I learned that the hard way.

 

[exp2000]

Re: Carburetor rebuild question

Careful with the B-12. It will destroy any rubber on the needle and seat parts. I learned that the hard way.

I did not see any rubber on needle or on the seat. I think seat on this carb is not removable. Hopefully, I did not make more damage than good.

B12 is STRONG, i wiped the parts of with terry cloth, set it on plastic table, and cloth fused with plastic, had to rip it off.