1989 johnson 25hp gas problem

[norman2013]

Hey guys, I have a 1989 25hp johnson that i am trying to get running well. It starts right up and runs for a little bit then dies off if i dont mess with the throttle. It has a little red gas lever that i believe leaks when it is open. Also I am wondering if the little screw on the top of the carb should be turned a few times either way or should it be tight? I will post a few pictures.

 

[norman2013]

Re: 1989 johnson 25hp gas problem

 

[racerone]

Re: 1989 johnson 25hp gas problem

The red lever is for manual operation of the primer.-------For running it should be inline with that valve body.----Is this motor " new to you " ?---------Has the motor sat for a long time ?----Close up picture of " the little screw " helps as well.

 

[pn]

Re: 1989 johnson 25hp gas problem

1 1/2 to 2 1/2 out from lightly seated position for idle air bleed, adjust from there, never tightly seat an idle air mix screw, you'll tear it up in a second. r u running on two cylinders? drop test. aso try pumping primer bulb or spring gas mix down carb to keep running. good luck.

 

[norman2013]

Re: 1989 johnson 25hp gas problem

Yes this is a new motor for me. here is a picture of the screw and a picture of how i believe this lever should be at. The motor starts right up. it runs for a little bit then will die off if i do not play with the throttle.

 

[Bosunsmate]

Re: 1989 johnson 25hp gas problem

Yes that is correct.
Give the choke a bump when it starts to die and see if that temporarily fixes the problem

 

[racerone]

Re: 1989 johnson 25hp gas problem

That screw is an idle mixture screw and it needs to be adjusted properly for the motor to keep running.-----Try starting with it 2 turns out and see what happens.------You may need to push the key in momentarily untill motor warms a bit to keep it from stalling.-------Is the thermostat installed ?------Did motor come from a dealer with some instructions / owners manual ?

 

[norman2013]

Re: 1989 johnson 25hp gas problem

No. I got a great deal from a friend so i jumped on it. I am not sure where the thermostat is located? I was told that this particular model did not have an airflow thing on the front of the carb in an earlier post. The motor ran much better with new plugs, a slight carb cleaning and the air flow screw out 2 turns. But still didnt let me put the warm up lever down all the way without stalling. I tried 2 1/2 turns down to 1/2 turn