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How to adjust lean/rich on 20hp Johnson

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daninski

Member
This topic has probably been beat to death so I'm hoping I don't get flamed too badly for asking this. I adjusted the lean/rich while at the dock and the engine I just bought started and idled much better then I adjusted it again while out on the water at a higher rpm. The engine runs better now at WOT and down then it did with with the lean/rich being set at idle. The two adjustments are like 1 turn apart from each other. Can anyone tell me the proper way to adjust this. Cheers
 
If it has a fixed high speed jet then the low speed jet is only functional at idle speeds.-----It is adjusted to get the smoothest idle with a bit of a stumble on rapid acceleration.
 
If it has a fixed high speed jet then the low speed jet is only functional at idle speeds.-----It is adjusted to get the smoothest idle with a bit of a stumble on rapid acceleration.
 
I've been told there is no hsj on my motor (20hp 1982-85?) I believe what your saying as that is typically how a lsj is adjusted but when I had the motor at about 2/3 throttle turning the jet in about 1 turn made the engine run smoother and feel better at higher speeds. Is this just my imagination? I do have Seafoam in the gas to clean my carb so could it be that my initial idle adjustment is wrong now that the Seafoam was added? Rigth now at WOT the motor is running a little better than when I first took it out about 3-4 weeks ago. I still haven't put the first tank of gas through it yet (not much time to spend on the water lately). I'll try resetting it at idle and see what happens. Any additional input is more than welcome. Thanks
 
Many folks will tell you " stories " and that will not go away anytime soon.---------I am sayiing there is a fixed high speed jet / orifice that meters the fuel at full throttle.-----It is found in the bottom of the carburetor bowl !-------The adjustable jet you see is for the low speed mixture.-----It is only for adjusting the mixture at idle speeds.
 
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