Carb trumpets

[2cams70]

The one I borrowed was a 5l capacity, an ebay import I guess. the liquid (again "borrowed") was by Allelndale Ultrasonics, not sure what it contains. It was like watching pirranah's nibbling away! Not promoting it but after a dismall attempt cleaning diesel injectors in a small ultrasonic I wasn't expecting much but pleasantly suprised.

I was going to glass bead outsides then ultrasonic clean - I was hoping this would clean the passages inside carb as presumably only gunge from sediment? Didn't want to remove sealing plugs if possible. How about squirting cleaner down the passages?

You used the same ultrasonic cleaning fluid as me. I'd strongly recommend the cleaning order I suggested earlier - i.e first clean in solvent, second ultrasonic clean, third hydro blast clean. Solvent clean first isn't that critical but I'd strongly recommend doing the ultrasonic clean before the blast clean and not the reverse. If you want to do another ultrasonic clean after blasting best do it with distilled water in the tank and not cleaning solution. Note that hydrobasting is much kinder and more "factory looking" on surfaces than dry blasting.

Insofar as the lower passages are concerned you can assess them by squirting a fluid (Eg. WD40, CRC CO cleaner, etc.) from a spray can with small tubular nozzle attached down each passageway in turn. If fluid comes out the other end you know it's clear (or reasonably so - more on that).

With my carbs one was completely blocked solid with sediment whist the other was clear. When I pulled the plugs out of the clear one however there was still a considerable amount of sediment attached to the walls of the galleries that could only be removed by insertion and hand twisting of a suitably sized drill bit.

I'm guessing one carb was blocked more than the other due to the way sediment flows in the fuel line. The carb at the end of the fuel line was blocked more than the carb where the supply is branched off from the fuel line.

One thing you have to be careful of if blasting is ensuring removal of any remaining left over grit. Removal of the lead plugs does assist with this.

It's up to you whether you decide to remove the plugs or not if they all seem clear. It is not without risk and you have to be very careful. I'm just relating my experiences.

PS. Note important point: If you do decide to remove the lead plugs DO NOT use a power drill of any kind. Use a drill bit in a hand held pin driver. Lead is soft and doing the drilling by hand is much more controllable.

[danbuoy1]

Thanks for thoughts and advice. I'm guessing the sediment doesn't dissolve with sprays or loosen with ultrasonic (tho was impressed at how it handled inside the jets circular cover - it was solid gunge couldn't even scrape with screwdriver), I'm just reluctant to remove lead seals as have to be perfectly refitted or leak. I'll give it a proper look first before deciding. I've only completely stripped one carb so far, using experience before breaking bits on the other - I'm finding a good dose of plus gas and time is working better than eagerness to get on!

Cheers

Paul

[2cams70]

Solvents and ultrasonic cleaning will not work on those lower passageways if they are completely blocked. Think of the blockage as being like a full length solid impermeable plug and you get the idea. The ultrasonics and solvents can only touch the ends of that long plug. They are unable to penetrate inside. The firmly packed solid has to be carefully drilled out.

The plugs need to be replaced if removed and you won't find replacements from a regular carburetor shop. Best source is from a gun shop selling lead (not substitute lead) shot. Most shot is lead replacement these days and real lead shot can be difficult to find. You could try and make your own lead plugs of course but I was able to obtain some from a firearms supplier. If all else fails and you can't get any you are welcome to send me a PM.

Note I see you are in the UK. Google "Clay and Game" in the UK. They are likely to be able to supply you with some suitable lead shot.

[joe7]

Interesting suggestion on getting lead from a gun shop. Made me think about it. Maybe lead would be easier to find at a fishing supply outlet that sells "sinkers". Or from someone that has old ones in their tackle box. I have several in various shapes and sizes. The ones that are round with a "slit" are installed on the line then crimped, might do.

[2cams70]

Interesting suggestion on getting lead from a gun shop. Made me think about it. Maybe lead would be easier to find at a fishing supply outlet that sells "sinkers". Or from someone that has old ones in their tackle box. I have several in various shapes and sizes. The ones that are round with a "slit" are installed on the line then crimped, might do.

I thought about using sinkers too. The lead shot is better though. It is more round, there's no split and you can get sizes around 3.6mm that fit perfectly

[SENC]

Great idea. I'm a hunter and shooter, so have shells with various pellet sizes. 1 shell would supply a bunch of carbs, so if you let me know what size I'd be glad to cut open a couple shells and to drop some in the mail to anyone in need.

[2cams70]

Thought I'd post some more detail on removing those lead plugs as it's easy to damage the carburettor if it isn't done carefully.

You need 3 things:
1. A set of graded in size small drill bits
2. A dental pick
3. A small hand held pin vice for the drill bits.

The lead plugs sit against a shoulder in the gallery (see picture). Do not go at it gung ho with a drill bit the same size as the hole the lead plug fits into. If you do you will enlarge the fuel gallery behind the lead plug. This gallery is of smaller diameter than hole the lead plug fits into. The technique is to start off with a much smaller drill bit and drill a small hole centrally right through the plug. Slowly increase the diameter until it matches the diameter of the fuel gallery. At this point you will just be left with a small sliver of lead remaining in the larger diameter hole the lead plug fits into. Pick out the remaining sliver of lead using the dental pick. All going well at this point you will have an undamaged fuel gallery and fully removed lead plug. Hopefully the pictures will explain.

I see on the internet that some people do it the lazy way and tap the hole and install a loctited in hex headed plug. Not me. It's not original and I'm unsure how well the loctite stands up to long term fuel immersion (not to mention how much of a pain it can be to remove).

[RichardHawkins]

2 cams,

Thanks for the advice, I was thinking of screwing into the lead plug, and then pulling the screw out complete with plug, hopefully. Have you tried this?

The finish on your carburettor looks lovely,

Richard Hawkins
.

[2cams70]

Thanks for the advice, I was thinking of screwing into the lead plug, and then pulling the screw out complete with plug, hopefully. Have you tried this?

Admittedly I didn't try doing it that way. I did notice however that the lead does form a surprisingly tight seal. When it came to removing the remaining lead sliver I had to dig into it with the dental pick and try and fold it over inwards. Even with just a remaining sliver it didn't want to just pull out.

Might be worth giving it a try. You'd only want a very small screw though - around 2.0mm to avoid damaging anything behind.

[RichardHawkins]

2cams,

Thanks, 2 mm is small, I will try, but can revert to your proven method if I get in a mess.

Richard Hawkins

[Craven]

Those shown channels are the feed to the starter jets, you will need a long series 3mm drill to clear them. I have used a small bead of melted lead, just drip onto a plate use rounded top into the recess.

[danbuoy1]

Interesting reading ideas, thanks.

Sorted my cleaning tanks out and started looking at carbs again. I'm presuming its the 2 small holes in bottom of float chamber that get gunged up? Squirted through carb cleaner in one and orangy stuff came out another opening so guess its clear but the other seems completely blocked. Are there any other ways of cleaning it (ultrasonic/carb cleaner etc) or should I just accept need to drill out the lead plug? If I do was thinking of melting wheel balancer weights?

Cheers

Paul

[2cams70]

I’m not really sure what more you are expecting. We’ve already explained to you at great length.

Personally I would not try melting lead into those galleries as you’ll just end up with galleries blocked solid with lead instead of dirt and I know which I’d prefer.

I’d suggest that you do a bit of research on the internet. There’s a Datsun website that gives good diagrams of the carburettor passages, where they lead to and the functions of the various systems in the carburettor.

One you have a good understanding of the whys you can then move on to the hows with a better understanding.

[danbuoy1]

Thanks for reply, I was just wondering if there were any other possible solutions to try before removing the plug, I'd rather that was the last resort.

However I left it overnight doused in carb cleaner and result! The blockage started to clear and can squirt through either way now. Realise there may be sediment left and not completely clean but hoping after a few more sessions it will be usable.

Cheers

Paul

[danbuoy1]

Bead blasted and cleaned, they look ok but still dull with visible corrosion marks, is it worth aly painting them? I did cylinder heads like this (on another car) and they looked like new. Or should I leaver alone?

Paul