How do I adjust the fuel/air blend ???

Lrdrlker

Seaman Apprentice
Joined
Jul 28, 2016
Messages
31
3 cylinder outboard engines are a completely different animal to me! It was always simple adjusting my chainsaw...2 screws..."in" is lean..."out" is rich. But 3 carbs all connected by linkage is new to me. I understand how they all run off the center carb and the linkage keeps them in check so they all do the same thing. I understand the cam but here's my question...it looks like the amount of air going into the carb can't be adjusted but the fuel is adjusted by the trolley wheel on the throttle cable and then once you get it to idle properly then you set the lower idle screw. Then you put it in gear and throttle up to WOT and set the top WOT screw. Is that it in a nutshell? That fuel trolley cable IS my rich/lean adjustment?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,953
A lot of your assumptions are wrong. Most modern outboards have idle mixture adjustment and fixed high speed jets. Johnnyrudes from the 50s and early 60s were the last to have adjustable high speed jets, Some newer motors do not have any carb adjustments for mixture.

Adjusting the trolley wheel increases air to the carb, plus increases timing, at the same air/fuel mixture. This increases idle speed.

You should pick up an OEM manual for your motor, as it will give link and synch instructions. You will want the idle timing and max spark advance set properly.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,074
Model # is ???----Agreed with the above.----Most modern carburetors have fixed metering jets.----Set at the factory.-----The maximum timing is fixed and set at the factory.----No need for a novice to try adjusting anything.-----Rather post what your motor is doing / not doing to see what might be wrong !
 

Lrdrlker

Seaman Apprentice
Joined
Jul 28, 2016
Messages
31
70EL77S I went out and REALLY FOLLOWED to adjustment to the trolley linkage and yes I can see how I went wrong with my explanation. Air/timing adjustment for sure. Thank you! I will be picking up a manual for my motor! Cheers
 
Top