Unstable bowl level after rebuild

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So over the holidays I finally got around to rebuilding my stock aisan carb. Followed pinheads videos and the FSM and all was well with the world. Got everything together and it ran great for about a week. Then a piece of dirt/debri made it's way into the carb and plugged up one of the jets. Pulled it apart, cleaned it, and then the trouble began. From that point on I cannot get the bowl from overflowing or running dry. It either A) slowly overfills the bowl so it floods at idle (runs great at throttle), or B) the level stays low (below sight glass) and runs dry under throttle (great around town, terrible on freeway).

I've tried adjusting it 6+ times. The FSM height of 6mm was way too high (flooded immediately), currently around 10-11mm and it floods, 12mm runs dry.... Float moves freely and nothing appears to impeding it's movement. I haven't touched it in a few weeks to give myself some decompression time and hopefully go at it again this weekend.

Ultimately I'm asking 1) Is there a common cause of this issue (besides user error)? 2) Do I just need to suck it up and give it a few more goes? 3) Is there something I'm just entirely missing?
 

OSS

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Replace the needle valve & seat. Make absolutely sure that the float isn't binding. Done.
 

OSS

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There might be crud in the needle valve orifice. Check the needle valve inlet screen too.
 

RAGINGMATT

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Agreed , Per @OSS

This is a Needle & Seat issue from debris stuck in or above the seat itself , When U did Your original rebuild U broke loose the metal Fuel supply line , hence shaking Loose the debris from age & time inside too

Do U Indeed have a needle valve inlet screen in place still or Missing ?
 
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The original screen is KIA, has a big hole through the screen.

During the process I removed the metal line and replaced it with rubber line and an additional filter. Old metal line was thuroughly bad on the inside.
 

NeverGiveUpYota

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In the rebuild you received a new needle valve seat and screen. I’m not sure why folks can’t see that. Are they saying there’s something amazing about the original screen over the one in the rebuild package?

I’ll ask have you considered a new float? 6mm is def potentially too shallow for the new rebuilds but 10-11 is huge. And 12 is even more deep, your 100% positive it’s running dry at 12 or is it just so full you can’t see the line? What happened to 7 or 8?

I rebuilt mine and a few times I’ve noticed changes in my float level. I’ve pulled it a few times and readjusted it and at this point “seems” fairly consistent.
I have another carb coming to me soon as a backup to rebuild so I’ll be curious to simply see what folks hit you with.
Also you could try an Okie Rebuild next time too before pulling the horn off. That helps suck crud thru the passenges.
 
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at this point the screen is no longer there, and my rebuild kit did not come with a replacement screen. I removed the metal line between the carb and pump and put on a rubber line with a second filter.

I'll get after it again this weekend and try finding any hangups w/ the needle/seat and float.

Now that I haven't touched it in a few weeks I feel like my eyes will be fresh looking at it again.
 

RAGINGMATT

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Kyster Brand Kits on the market now Do Not Come with a brass inlet new screen

I have made one by using a Bathroom faucet Solid Brass Screen , then Forming it over the end of a #2 Pencil eraser Tip to obtain the Cylinder shape needed to insert in the air horn hole where it goes
 

SteveH

 
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I accidentally lost the tiny spring that lives inside the needle when I was adjusting the float height on my FJ40. After that, the fuel bowl level was erratic and wavering. The engine still ran surprisingly well.

When I found the tiny spring on the garage floor (!), I put 2 and 2 together, and took the carb apart and replaced the spring, and of course, the float level was rock solid after that. The 'needle' was comprised of the needle itself, this small spring, and another small post (for lack of a better term). Very easy to misplace/dork-up those parts, as I did.
 

RAGINGMATT

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Both Manuals were issued to me when I entered The Toyota T-TEN Technician Program circa. 1994 , There educational Instructional material
, Theye were Never part of a Dealership's Print media service Dept Library

How Does one scan a 1" thick book page by page ?
 

gregnash

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Both Manuals were issued to me when I entered The Toyota T-TEN Technician Program circa. 1994 , There educational Instructional material
, Theye were Never part of a Dealership's Print media service Dept Library

How Does one scan a 1" thick book page by page ?
To answer your question... very slowly, page by page!!! LOL. (On a flatbed scanner)
 
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