Misfiring at idle

[ksingler]

I have a 1985 85 HP Force OB.<br />Under normal operating conditions, the engine runs well and has good power.<br />At idle conditions, the motor misfires, and acts like its backfiring. The mis/back fire is so strong that it sometimes causes the motor to stall. The engine will start right back up and run again until it has a mis or backfire strong enough to stall it.<br />Any help or suggestions in how to diagnose the problem would be greatly appreciated

 

[The Marine Doctor]

Re: Misfiring at idle

As it starts to cool off outside, you may need to open the low speed jets to give the engine more fuel. They are located on the carbs and can be adjusted with a thin slotted screwdriver.<br /><br />Turn them 1/8 of a turn counterclockwise.<br /><br />TMD

 

[force01]

Re: Misfiring at idle

Turn all of your low speed mixture screws in until they lightly seat. You have 3 of them 1 on the front of each carb. Back all screws out exactly one turn. Adjust your idle speed to about 1000 rpms out of gear in the water. put your motor in gear at idle speed turn your mixture screws in 1/8 of a turn all carbs and wait 30 seconds keep screwing them in until the motor starts to lean pop this is your lean setting. Back out all screws 1/4 turn from there. If the motor runs fine adjust your idle to 750 in gear, if you motor still lean pops back all your screws out 1/16 of a turn. keep doing this until your lean pop goes away. if you get beyond 1 3/8 of turn from seated there is something wrong with your carbs and you will have to rebuild them. good luck, bret<br /><br />If you need further assistance please email me @ forcepower01@yahoo.com.