Johnson 1990 15hp J15RESR gas/oil problem

[ahlangle]

Engine cranks, then dies after put into gear and given gas, unless I choke it at which point it runs high and dies shortly thereafter.
Could it be the fuel/oil ratio is off? Could it be the "Low speed adjustment knob"? (What does that knob control?)

 

[CMOS]

This could be any number of problems however, start with the simplest possible problem: remix your fuel, clean or replace the plugs, and try again. After that you just may need a Carb kit done.

The Low Speed Adjustment Knob allows you to adjust the fuel-air mixture (rich or lean) on the Carb.


CMOS

 

[ahlangle]

Is there a position I should leave it dialed all the time or change it? If change it, how will I know when to do so?

 

[CMOS]

Is there a position I should leave it dialed all the time or change it? If change it, how will I know when to do so?

There is a specific setting for each carb. You'll either need a Service Manual or one of the members here maybe able to help. Essentially you will screw IN the low speed jet all the way, then back it out a specific number of turns. That's you starting point.

Go to the web site LeeRoys Ramblings and see if you can look up your motor. He's got a LOT of detail on that site.

CMOS