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Dose anyone know how many turns out the carb air/fuel mixture screws should be
Air/fuel mixture on B20A3
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Did you check the pdf manual on how to trouble shoot your carbs?
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Yea but it dosent say anything about how many turns out it should be.
For tuning you typically have to adjust the linkage to balance the carbs using an airflow meter. There's also the idle screws to keep it at about 800rpm when engine is at temperature. Before messing with the mixture screws, try balancing the carbs. The manual doesn't specify what the "default" setting is.
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1funryd. hello super moderator… I see you have been posting here for a long time and have read many… I have an 88 S B20A3 what I understand… so the problem has been that the motor runs pretty good at start up… and casual cruise around the neighborhood… but when I take it on the city streets and drive at speed (40-45mph) constant it takes about a mile or so the motor loses rpms and then dies… I coast to a stop and have to restart… its alittle tough starting but does so and then runs fine again just putting around the neighborhood… I have looked thru the manual and done some of the simpler things… O2 one sensor replaced PCV replaced… bled the coolant… and also put new roders and pads in the front… I get a 10 code from the ECU
but am dreading the carburetor rebuild… my hypothesis would be the floats are emptying and can’t replenish fast enough… and basically the motor is running out of gas and takes some time to fill up again and provide fuel to the moto… very frustrating… one other thing I can mention… from a dead stop there is a lag pressing the gas pedal so I have tomwork massage the gas pedal to get it moving and has a bit of spung… so this sounds odd but Ill say it runs pretty fine until it doesn’t any tips or suggestion you or anyone else in the group
but am dreading the carburetor rebuild… my hypothesis would be the floats are emptying and can’t replenish fast enough… and basically the motor is running out of gas and takes some time to fill up again and provide fuel to the moto… very frustrating… one other thing I can mention… from a dead stop there is a lag pressing the gas pedal so I have tomwork massage the gas pedal to get it moving and has a bit of spung… so this sounds odd but Ill say it runs pretty fine until it doesn’t any tips or suggestion you or anyone else in the group
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Have you had a professional diagnose the issue?
I would start there and then you can focus on whether you will want to fix it yourself or pay the cost to have some professional fix it.
Carbs are so unsupported these days, my only recommendation is too just get rid of the platform, and do a Fi swap with another B20a or do a complete swap and go B20b/z (crv) swap Fi.
Trying to keep those carbs supported is really hard and actually more custom than doing a complete swap these days.
I've owned two carbie ludes. Thankfully they both ran okay and I didn't have to dive into troubleshooting anything. Having said that, even when they run well they are woefully underpowered. If you have the means to do a swap to fuel injection I highly recommend it if you want to keep this car. But I understand that someone might not want to do that, for whatever reason (budget, lack of knowledge, wanting to keep the car original). Here is a write up for adjusting the dual carbs on these cars...
www.preludepower.com
Keep in mind, there are a lot of vacuum lines which control everything. There are also sensors and other control mechanisms with rubber diaphragms. All of which can deteriorate over time, so it's possible there's more than one problem with your carbs. The carbs on these engines are side-draft carbs, much like those used on older motorcycles. Some members have had better luck taking their cars to a motorcycle shop for diagnosis. Best of luck with your car issues.
B20a3 Carb Adjustments Write-Up and ECU Error Codes
This write-up is meant to solidify some facts about the dreaded B20a3 engine. This mostly is meant to cover some basic adjustments of the carberetors. I have succesfully rebuilt my carberetors and tuned then to the optimum capacity with the tools I have. I took all of these pictures of my own...
www.preludepower.com
Keep in mind, there are a lot of vacuum lines which control everything. There are also sensors and other control mechanisms with rubber diaphragms. All of which can deteriorate over time, so it's possible there's more than one problem with your carbs. The carbs on these engines are side-draft carbs, much like those used on older motorcycles. Some members have had better luck taking their cars to a motorcycle shop for diagnosis. Best of luck with your car issues.
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