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Some of you might know I've been debating about swapping the engine out of my Brumby for my other engine to get a few more beans. This is now definitely happening but I wanted to first give some attention to the carby to see if I can't fix a little issue it had and get some better economy.

Carbie kit arrived yesterday (Thanks again FROG!) and today I should have been welding on the wagon but my dremel decided to crap out this morning which ended that idea. So I couldn't waste a whole day, decided to have at the cabie since I had a full can of carbie cleaner lying around. And this is the write up of what I did today. I didn't go as far into it as what some might call a complete rebuild, I just took it apart, cleaned everything and put it back with some new parts. Somebody has done this before since there were some bits missing. I've rebuild one of these before and it's very straight forward...but it didn't end well for other reasons not gone into here

My carbie is a manual choke and very simple, some are auto choke which I have no experience with and can be a bit more complicated on top.
So firstly you take the carbie off the inlet manifold and set up a clean space on your bench. Get yourself setup with something comfortable to sit on, something to listen to and your carbie, rebuild kit, tools within reach and the destruction manual. I also had an ice cube tray to put all my crucial tiny jets and air bleeds in individually with labels. Also a good idea to give the carb a rough clean down to get rid of the large chunks of gunk that builds up (why is this stuff always brown?) I didn't do this and kinda regret it.


Start dis-assembly by removing the solenoid at the front (big hex thing) and the choke cable bracket at the back (2 screws) Remove the two return springs on the choke and throttle linkages and undo the screw that the accelerator pump pivots on. Remove the pivot arm from the accelerator linkage. Then remove the choke linkage (split pin, washer, spring) from the choke shaft.

Now you can undo the remaining 3 or 4 screws holding the upper plate to the float bowl/lower assembly and remove it. Be careful here as you are now into loose spring and ball territory. DO NOT turn the float bowl upside down whatever you do, there is a spring, ball and weighted pin sitting loosely inside. If these fall out you will never know where they came from. Here I removed the float and fuel needle from the upper plate and set them all aside. You can also remove the secondary throttle diaphragm (big can at the back) if you have it, there is a gasket between it and the carbie itself.

Fuel needle and float removed:


Now this is where things can get a little complicated. On the lower part you will see the tops of all the jets and plugs screwed in. Each of these does a very specific task and they are all different. It is very important that these go back where they came from when you're done. Draw a diagram of the top and the location of each jet/plug and at which point they are tightened up (flat head screws pointing to 1 o clock, 6 o clock etc)
You need the book or assembly sheet here to label each jet as you take it out and put it in its own separate container. Now you can remove the spring and ball from the accelerator pump bore (label them!) and the weighted pin from the D shaped hole next to the pump bore. Make sure you know which hole it came from.

Individually labelled:


Now remove the two main jets accessed from the bottom of the carb below the float bowl. Two 12mm hex plugs hide the jets themselves. One is the primary main and the other is the secondary main, again don't get these mixed up and make sure they go back in the same place when re-assembling.

Here you can separate the throttle plate from the float bowl. There is one big screw going in from the bottom which is hollow (don't get it mixed up) and two phillips head screws going in from the top. These seem to be always super tight and have difficult access to be careful not to round them out. Before you remove the idle mixture screw from the throttle plate wind it all the way in until it seats, counting the number of turns. You'll need this when you put it back in to get it somewhere in the ball park for your idle mix. The needle has a spring as well as washer and an O ring that need replacing with new. You can check the throttle shafts for play as well, mine had a little bit but not huge. This wasn't a complete as new rebuild anyway so I just left them.


Now take the float bowl somewhere outside with a container and a brush and blast it all out with carbie cleaner. Clean the outside with the brush and then the inside by spraying cleaner down every hole where the jets were. Down the accelerator pump bore, into the float bowl, into the venturis, every hole you can find spray some in and then in the opposite direction. Don't be scared and use lots of cleaner. Set that aside to dry while you clean out all the jets one by one; spray some cleaner in them so it comes out the little holes. Also clean the throttle plate butterflies and the upper plate passages, through the needle hole etc. Don't use a wire brush or anything abrasive on the jets, damage them and they won't work properly.

Here is where you replace the throttle plate, using a new gasket (very thick gasket) Study the destructions and diagrams carefully so you can put all the jets back the way they were. First the main jets at the bottom with new washers and their plugs, then put the air bleeds and jets back one by one with their plugs and tighten them down so they match your drawing from earlier. Replace the weighted pin in its hole and the ball and spring. The rebuild kit should have new balls (:rolleyes:) so put a new one in making sure it's the same size. You can replace the secondary throttle diaphragm as well with a new gasket. The linkage at the bottom connects to the secondary butterfly shaft and has a circlip to secure it. Replace the idle mixture needle as well with a new washer and O ring, winding it in until it's seated and backing it out the number of turns you counted earlier.


Take a look at your old fuel inlet needle and the new one. Mine were a completely different design so I had to adjust the float level after installing them. My kit didn't come with the little mesh filter though so I had to carefully take it off the old needle seat and put it on the new one.
Old needle with filter above, new needle below. There is also a little wire clip that holds the needle into the seat.

To adjust the float level: install the needle and seat and then the float. Hold the plate upside down and with the float just contacting the needle measure the distance between the bottom (really the top) of the float and the surface of the upper plate. Depending on your carb this should be around 10-11mm. Mine was 10.5. If yours is out after the new needle take the float out and bend that little tab very slightly. Re-install and measure again making adjustments until it's correct.

Now it's time to replace the upper plate on the float bowl. But first you have to install the new accelerator pump. In this kit it has a leather skirt and needs softening up before installation. I soaked it in some petrol and poured some down the bore as lubrication. Carefully work it into the bore twisting and turning it as you go, make sure not to turn the leather skirt inside out or get it creased up. Because it sits on a spring it will most likely pop straight back out. So select your upper plate to float bowl gasket first comparing it to the old one. There are a few different ones so make sure no jets or holes are blocked up.


There's a bit of a fiddle here while you get the upper plate back on while holding the accelerator pump against the spring. Be careful not to knock the float off its pin as there's nothing holding the pin in place. Lower the plate down with the gasket seated nicely and put a couple of screws loosely in to hold it down. Two of these screws hold the choke cable bracket down so don't forget it. Also one or two are longer than the rest and need to go into the two deeper holes. The carb is now almost back together! just the linkages to sort out.

Choke cable bracket:

mmmm, benzine tainted ice cubes next heat wave

There is a new rubber seal in the kit that goes over the accelerator pump. It can be annoying to get it in so you can put a little thin oil on it so it slips into the casting better, it also seats in a ring at the top of the plunger.



The accelerator pump pivot arm is a bit fiddly to install as it's on a spring, and the pin goes into the accelerator pump plunger. There are two washers between the arm and the carbie, and the arm pivots on a small parallel part on the screw. You have to connect the linkage from the main throttle shaft first before you install the arm. From here it's just a matter of reconnecting all the linkages and springs and making sure everything works. There is a new split pin in the kit for the choke linkage.
Don't forget the big hexagonal solenoid at the front of the carb.

And that's it! the carb is done. As I said you can go alot more in depth with a rebuild to make it like new but I wasn't doing that. Last time I did this exactly the same way and the car fired up on the first crank and ran beautifully for about 3 seconds until the other thing happened...not carb related
It really is a breeze as long as you label everything, take your time and read the book properly, easily done in an afternoon. Also make sure when you're putting all the jets and air bleeds back in that there is no dirt or grit around to get trapped in the carbie. I turned over the shirt that I was using as a work surface to the clean side And as always use the correct tools for the job and you'll have no problems.

Now seeing all this you can decide to do it yourself...or just go with a Weber

The completed carburettor!

steptoe wrote:mmmm, benzine tainted ice cubes next heat wave

You don't re-use the ice cube tray afterwards in case you hadn't noticed

well done and a nice article that should be linked to the wiki, but... remember to remove the rag from your manifold this time

benzine and other aromatic hydrocarbons mmmmmmmmm ... captain goodvibes would be back for seconds.

and for that brand new carby look... sit the whole thing in truck wash mmmmmmm caustic salts mmmmmmmm


TOONGA

You can use GP paint thinners to clean the carby bits, its better than carb cleaner, easy to get and cheap, just dont put it on any plastic carbie bits or ice cube trays.
Its a good idea to spread/stretch/oil the acc pump cup, before you put it in, it will last longer.
Also worthwhile checking that the sec diaphragm holds vac.
When finished and on the car, check to see if the fuel level lines up with the dot on the inspection window.

During this I found something interesting and maybe disturbing on the engine itself which has been stored outside (under cover)...we get many different types of mud dauber wasps building nests all over our walls and in any small cavity they can make or find. They come in all sizes from bigger than a bee to miniscule. This time they found an open hose somewhere on the engine and have blocked up the tiny vacuum lines to the carb Could see sand blocking up one of the tubes so push a piece of wire down and a half morphed wasps larva pops out and a husk of a caterpillar, There was also a mud blockage in the carbies fuel inlet pipe...how many more of these could there be??? I'm gonna have to disconnect and check every hose now

tambox wrote:You can use GP paint thinners to clean the carby bits, its better than carb cleaner, easy to get and cheap, just dont put it on any plastic carbie bits or ice cube trays.
Its a good idea to spread/stretch/oil the acc pump cup, before you put it in, it will last longer.
Also worthwhile checking that the sec diaphragm holds vac.
When finished and on the car, check to see if the fuel level lines up with the dot on the inspection window.

All of the above, and also easier to fit the accelerator pump plunger rubber boot into float cover prior to fitting the cover back on. Standard practice for all carbs with plunger boots.

Well done Silverbullet on reviving the hitachi rather than going for the fuel guzzling weber conversion!

Rodeo4Jake will probably have a smile on his face when he reads this!

Cheers

Bennie

In my experiences with Webers, if they are fitted with the correct jets and tuned, then they use less than the standard carbys. Unless you drive them very hard all the time.

In my experiences with Webers, if they are fitted with the correct jets and tuned, then they use less than the standard carbys. Unless you drive them very hard all the time.

Yes thats true, but Webbers encourage you to drive hard, with the power and sound, standard carbs don't.

So, Webbers drink fuel, because you have to:D

tambox wrote:Yes thats true, but Webbers encourage you to drive hard, with the power and sound, standard carbs don't.

So, Webbers drink fuel, because you have to:D

Yeah Greg I understand, when you have power, you must use it

tambox wrote:Yes thats true, but Webbers encourage you to drive hard, with the power and sound, standard carbs don't.

Like my EJ22 and it's exhaust - I drive it harder than the liberty But I probably get better economy than I would with an EA81 and a weber driving it the same And there's more power!

Cheers

Bennie