2004 Merc 4 Stroke 90 will not idle!!

[cgs]

Serial #OT 943879 motor idles fine for a few minutes at first start up, then idles very rough, have to keep playing with the throttle to keep it going, primer bulb is not real hard after a few minutes. Then after pumping bulb it still will not idle smooth. Runs great at higher rpm's but when you return it to idle it is real rough. Carbs have been cleaned and rebuilt, new plugs. Any ideas?????

 

[crappiejig]

Re: 2004 Merc 4 Stroke 90 will not idle!!

Was a carb sync performed after the rebuild? Very important on these 4 strokes.

 

[cgs]

Re: 2004 Merc 4 Stroke 90 will not idle!!

Lets see the motor had the same symptoms before the carb rebuilds, going to do the carb sync tomorrow, used an ext fuel tank to eliminate those problems, compression test was good, spark was good, new spark plugs that came out 2 and 4 were wet with fuel and 1 and 3 looked to be burning fine, it did seem to be coughing a bit after warm up, merc techs think it is a stuck intake valve they are going to clean out the carbon with power tune or something, wondering if it could be a thermostat since it runs great the first three minutes after start up

 

[cgs]

Re: 2004 Merc 4 Stroke 90 will not idle!!

carbs are all in sync then the tech adjusted the pilot screws with a tach but it still has a lean cough. Anyone have any ideas?????