Does anyone know of a web site or have information available for the proper sequence of adjusing all the different idle adjusting screws on the 1986-89 Accord carburator? I cleaned the carburator (which was full of dissolved filter material) and repaired all the broken diaphragms attached to the carburator, but am at a loss how to correctly adjust all the idle adjustments that this carburator has.
TIA Bill
You might try the free online Accord manual at
The Prelude factory service manual at
wrote
To set the fuel mixture manually, you'll need to perform a propane boost test. The tool distributors make an expensive special tool for this but you don't need it. Just get a regular propane torch and remove the flame tip. Now, attach a section of plastic tubing about 5 feet long. Attach a tachometer, and with the car running, remove the top of the air cleaner and slowly feed propane into the primary barrel of the carburetor, i.e., open the torch's valve slowly and continue until the idle peaks out (but stop if it's more than 500 rpm you may need to adjust the idle mixture screw before proceeding). You should get an idle boost of about 100 rpm when the fuel mixture is set correctly. Adjust the idle mixture screw so that you get the correct amount of boost. Afterwards, set the idle speed screw to the specs on the underhood sticker, usually about 800-850 rpm for a car with a manual transmission, and recheck the timing.
Eric
That's IF you have a carb with a idle-mixture adjustment screw. Some models don't have it.
I've never seen a Honda carburetor without a mixture screw. However, on many models, Honda installed a metal guard type plug over the mixture screw. The mixture screw can still be accessed but the plug has to be removed first and this usually requires removing the carburetor since the screw is at the bottom back end of the carburetor next to the firewall.
Eric
I forgot to mention that the first step is usually to set the float height. There should be a window on the side of the carburetor with a black dot at the center. The float height adjustment is correct when the fuel level is at the center of the black dot in the window.
Eric
All the information was terrific, I will never buy a carburated engine again. FI is much simpler to repair due to the fewer parts. Thanks again
Bill
That could be why I've never found it... but then I've never seen any mention of it in any shop manuals either. The consensus on another board is that mixture is controlled by the "ECU" (such as it is) and isn't user-adjustable on the third-gen Accords.
The procedure is described in the factory service manual from Helm. It's on page 11-22 in my copy. You can get one from
While it is true that Honda used feedback carburetors for fuel control under different driving conditions, the base fuel mixture is set via the screw at the back of the carburetor. The factory service manual actually specs a propane boost of 60 +/- 20 rpm. However, a boost in the range of 75 to 100 should be fine as per my prior post. When servicing a Honda carburetor, I've found that it's best to follow the directions which are included in Honda's factory top clean kit. This kit was put together many years ago by a dealer Honda tech who developed a relatively fast and easy way to service Honda carburetors without removing the carburetor from the manifold. The kit even includes a replacement o-ring and washer for the idle mixture screw. The only problem is that you need to remove the carburetor in order to access the screw on cars with the mixture screw cap. The top clean kit also does not include floats which must be purchased separately if needed.
Eric
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