AQ 120b float setting

[dgabler]

Downloaded document from Don S in thread 265817. Same as the manual I have. In it is talks about checking the float level and that you need to make a template. I do not understand the diagram at all! Also it says :

The float level is checked by measuring the distance from the float's dividing line to the upper edge of the float (needle valve closed). The distance is to be a max. of 26mm (1.023 in) and a minimuim of 22 mm (0.866 in) and the min. float level is at 26 mm (1.023 in).
Here is the image:

first, what is the floats dividing line, the center of the plastic floater circle?
Even then what is the top measurement of 22-26mm based from?

Rebuilt the carb but never re-adjusted the float setting and now when under load at ~3100 rpm engine dies from fuel starvation. Suspecting that the float is to blame.

Thank you.

 

[cr2k]

Re: AQ 120b float setting

Boy that is confusing. I am guessing what they mean by float's dividing line is the where the float bowl and carb body meet. That is shown as 26 mm on one side and 22 on the other.

 

[captmello]

Re: AQ 120b float setting

Here's how I read it. The dividing line is the seam in the float where the the two halves of each float are joined.

I looked at the Seloc Manual, which has its limitations, i know, but has some better descriptions. It says:

"to adjust the float position, hold the carb at a level attitude, as shown, with floats facing upward. Now, measure the distance from the machined surface of the carb to the bottom of one float as indicated (there is a pic). This measurement should be min. 7/8" (22mm) and max 1 1/23" (26mm). Check the other float in a similar manner. The measurements for both floats should be the same. The obtain the proper measurement, CAREFULLY bend the hinge tab up or down."

In the pic they are measuring from what would be the top of the float (the seam in the float), now the bottom since its upside down, to the surface of the carb body with the float lifted out of the carb body which would be its lowest position if the carb was turned rightside up.

Hope that is understandable.

 

[dgabler]

Re: AQ 120b float setting

That makes sense. Now what part of the carb body are they measuring from in the Seloc Manual?

Should there no be some talk about open/close touch points for the valve. E.g. @ XX mm the float plate should just be touching the needle valve at YY valve should be fully closed.

 

[captmello]

Re: AQ 120b float setting

the machined surface is the flat surface the float bowl seals against.

By setting the float height, you are adjusting the opening of the float needle valve.

 

[dgabler]

Re: AQ 120b float setting

THANK YOU.

Took some measurements with the floats up/down against the surface and got this for the floats up:

and down

Now I understand the template that Volvo made! The template is exactly that, a template that is dual sided. The template is flipped over to measure max or min. The rest of the crud in the picture is a cutaway view of the carb that is poorly represented. they should also include a plan view.

So the volvo wording translated differently should read:
The float level is checked by measuring the distance from the top machined surface of the bowl to the upper edge of the float when the needle valve is closed. The distance should be a a max. of 26mm (1.023 in) and a minimuim of 22 mm (0.866 in)



Now the biggest concern I have is that according to the float down picture my floats are 8mm out of alignment. This sounds huge to me.

 

[captmello]

Re: AQ 120b float setting

Yes, I think your close.

I think the measurement you want is in your second pic. It's at 34mm now and should be 22-26mm.

It's interesting how the OEM manual says you can't adjust the float, but the Seloc manual says "carefully bend"...

BTW I think the Seloc manual is incorrect and shows the measurement being taken like your first photo that is at about 10mm.

Anyway, The way I'm seeing it, the float in its current state would need to drop 34mm to fully open the needle valve which is too far and may even be bottoming out on the float bowl before opening completely, not allowing enough fuel at high RPM. Just like you were thinking originally.

I guess if it were me, I'd try the "Bend Carefully" method. You can always buy a new float if it doesn't work out.

Let us know how it goes.

 

[dgabler]

Re: AQ 120b float setting

Fixing the float level made the boat run like a dream! Great day at the lake.

Had to bend the floats like crazy to get them down to the right level but it worked!