Reply To: 1966 Johnson MQ-12a service manual

[grunt311]

Checked compression 72 psi and 70 psi

Carb is very clean. When i tore it down it was not in bad shape fairly clean. When i start the motor and run at half choke its seems fine. When the choke is opened up it begins to cough. Tried the low speed needle adjust both in and out with not much luck. Started at 1 1/2 turns out  and went out to 3 turns out. Then in to 1/2 turn still the coughing. If i push in on the washer on the low speed needle it seems to get slightly better. Could it be it is sucking air past that o-ring? The o-ring is seated correctly but it seem like an odd set up with very little compressing the o-ring to create the seal.

Thank you guys for the help on this one. I have three early 50’s Johnson’s i have rebuild so this one is pretty modern for me.