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Unlike other Lawn-Boy carburetors, this one's needle is at the top of the carburetor, the needle goes directly into the fuel nozzle from the top. The carburetor is black plastic. There's no spring. It's brass. It takes a 1/4" wrench to adjust. I could not find this carburetor in the big Lawn-Boy manual.

Most of the Lawn-Boy carburetors have the needle adjust on the side of the carburetor, screwdriver adjust, and spring tensioned to keep them from vibrating out of adjustment. This is NOT like that at all.

It is used on 1984 Supreme models 7232, 7271, 7271AE, R7271, and R7271AE for sure.

Does anyone know how to adjust this kind of needle valve, or where to get the procedure for this one?

Sounds like a Lawn Boy D-400 series carb. Maybe this old service manual will help you out. https://dokumen.tips/documents/26622228-lawn-boy-service-manual-1950-88-complete.html

Or maybe on this website.

Rivets said:

Sounds like a Lawn Boy D-400 series carb. Maybe this old service manual will help you out. https://dokumen.tips/documents/26622228-lawn-boy-service-manual-1950-88-complete.html

Click to expand...

Thanks for the post. The D-400 carburetor has a needle at the top, but that's where the similarity ends. The manual you linked to is the "big Lawn-Boy manual" I was referring to, I was really surprised to not find this carburetor in there since it claims to cover the 1984 model year. Could it have something to do with the designation "Supreme Models"? Anyway, I don't want to start a carburetor guessing game so I took a picture of it. Seen one of these before?

Oh, it also has a Toro part number: 92-9696. Every Lawn-Boy plastic carburetor I've found with a Toro cross-reference has been 92-9697 (one off, heh). If I was a betting man I'd say the 92-9697 has the needle sticking in the side of the carburetor.

intruder1500 said:

Or maybe on this website.

Lawn-Boy

www.mytractorforum.com

Click to expand...

There went two hours of my day. There are some interesting downloads there. I had no Idea there were Johnson 2-stroke powered washing machines. I tried to picture my wife mixing up premix for her washing machine...I just couldn't see it!! But making the basement smell like Klotz...hmmm.

Found it! It actually is in The Big Manual (369 pages, 144MB, a long download)! It threw me off because the title continues onto another page, but changes to a different carburetor (with a different carburetor's drawing). But when I looked close at the photo, the guy had a wrench on an adjustment at the top of the carburetor. The name for this carburetor is "F-100-300 Series Carburetor with Adjustable Fuel Flow Needle Valve". Hopefully by typing it all in it'll be easily findable for future readers. It's ONLY on page 90 (page 91 is a different carburetor) of The Big Manual.

I think (correct me if I'm wrong) the difference between the carburetor descriptions is that mine is a "Vented Carburetor" and the other (with the needle on the side) is a "Primer Activated Vent".

Pictures always clear some things out.I still have that specials wrench and did some adjustment.With out that thing it tuff.did adj,while engine was running.