Hi all,

 

So I'm rebuilding my Hitachi EA82 carby according the Gregorys workshop manual and I've a hit a snag in dismantling the top cover.

 

After removing the float, I am supposed to remove the needle valve seat assembly (the brass colored thing in the image below) "using a screw driver". What do they mean by that statement? Am i supposed to just jam a screwdriver down the side and try and pop the whole assembly out? Or am I supposed to use a large slot screwdriver to rotate/screw it out (there is a slot in the top)?

If it is the latter - I tried and tried to unscrew this (anticlockwise) but it just started burring the slot.

 

Anyone done this before and know how it is supposed to be removed??

 

Edited February 28, 201214 yr by fishboy
New question added to thread

Hi,

 

Good description, and yes, anticlockwise it screws out. Try penetrating oil or throw some heat on the carb body.

 

First one of these I did, I selected some of my screwdrivers and custom ground them to fit all the various screw slots. Like the power valve, and the one you're working on.

 

Often times, a tight precise fitting screwdriver and just bearing down on it and turning may pop it out. Without destroying anything.

 

On the other hand, I've had a few where I dribbled some weak acid solution around them to get then loose.

 

Let us know how it goes.

 

Doug

Thanks Doug!

 

What's the best way to apply some heat - with a hair dryer?

Thanks Doug!

 

What's the best way to apply some heat - with a hair dryer?

 

Hair dryer won't get it hot enough. You need a handheld propane torch

Ah, okay. Where would you apply the flame - directly to the aluminium or to the brass bit?

(sorry - I'm new to this..)

Ah, okay. Where would you apply the flame - directly to the aluminium or to the brass bit?

(sorry - I'm new to this..)

 

I have never personally done it so maybe someone else can chime in

I've used a propane before, just on the aluminum. It doesn't take much to expand it a little.

 

Doug

BIG screwdriver. It'll come out.

Yeah you need a large screwdriver. Also often helps to give threaded items like that a sharp blow with a hammer/punch - breaks the corrosion bond.

 

An impact screwdriver would be perfect but you would have to custom grind a bit to fit that seat. If it were really stuck then I would probably sacrifice a socket extension and grind it to fit that slot then use the impact driver.

 

GD

It looks like I've burred the slot on the assembly bit trying to free it. Is this going to affect the function of the carby?

No - as long as the needle can move freely and will seat in the bottom it will be fine. The top where that screwdriver slot is located is not a critical surface.

 

GD

Apologies for being pedantic!...but are you sure I can apply a butane torch flame to the aluminium? Wouldn't it quickly melt/deform he aluminum top cover?

Wouldn't it quickly melt/deform he aluminum top cover?

 

No. It will be fine. Just heat - don't keep going till you melt the thing. Generally speaking, while the flame is technically hot enough to melt aluminium, a casting the size of a carb top would take more BTUs/Hr than a small propane torch can put out to heat it to melting temp. This has to do with flame size, temp, and how much heat you can actually impart to the object being heated before that heat escapes.... aluminium disperses heat very, very quickly.

 

GD

Okay, thanks. I'll let you know how I go!

Do you have a rebuild kit? Or are you just cleaning and resealing?

 

Whenever I do these with a rebuild kit I just tap a screw extractor down the center bore of the needle seat and unscrew, takes 2 seconds. It will mangle the seat a little bit, but if you are replacing it anyway who cares. If you aren't replacing it, then don't do that.

Ferox - I have a rebuild kit but totally thought this seat wasn't included...but on closer inspection it is!! I will definitely give the screw extractor a go in this case.

 

Thanks. And thanks to all for your advice so far!

So I just had a good look at the replacement seat and it is a bit different to the existing one. The one currently in the carby appears to have 6 holes in it, whilst the replacement one only has 2 larger holes in it (see pic).

 

Is this likely to cause a problem?

 

No,the important part of the valve seat is the size of the hole where the valve seats.

Bigger hole = more pressure on the valve resulting in a higher carb fuel level for the same float setting.

The seat that comes with the kit has an outer diameter which is slightly smaller than that currently in the carb (existing one is 12mm, the replacement one is 11mm). The inner diameters look about the same though. See pic below. Addionally, as I said above, the replacement seat has fewer holes around the bottom than the exisiting one too.

Can anyone suggest whether this new seat is still going to be okay?

 

The only reason I ask is that it looks like I am going to have to destroy the old one getting it out (via screw extractor), since all other suggestions so far have failed including heating with butane torch

 

...anyone?

Looks like it should be fine. I would trust that someone probably tested this combination if it's in a rebuild kit. The inlet needle's and seats always look somewhat different in the generic kits I've found.

 

GD

I'd like to trust them, but sadly the company (called "FuelMiser") here can't confirm that it's definitely the right kit. The only information they have is that it should fit Subaru L Series up to 1989 (mine is 1991). They have no other kits to fit later model cars.

...anyone?

 

Don't know what's been said by other person, but the top diameter isn't important. So long as the threads and seating of the new on is the same. More or less holes won't make a difference either for a street car.

 

Twist it out with an extractor if need be. There is an inlet screen/filter on the bottom of the piece still in the carb. They are typically clogged/on their way to clogging.

 

Doug

My goodness. So I got the seat out with the extractors..woohoo!

 

JUST when I thought I was on my way - I go to remove the Primary Slow Air Bleed (see pic) and it's similarly stuck! Only this time I definitely DON'T have a replacement. So...is it really necessary to remove this when cleaning/servicing the top body?

 

No, it's not that critical that you remove that, just make sure that all the passages connected to it are free and open.

 

If you have a screwdriver that fits it like a glove, push down on it and give it a bump clockwise. You may feel it give a little bit. You can even try tapping the screwdriver with a small hammer. Then try to turn it counterclockwise.

 

At any point you believe you're distorting the slot in the air bleed stop.

 

good luck!

 

Doug