1999 60 HP Bigfoot Coughs at Idle

[seaway81]

I have a 1999 Mecury Bigfoot that has started to cough at low RPM or when I bring it down from cruise to a lower RPM. I can feel the motor slow when it coughs. At cruising RPM the engine runs very well, quiet, smooth and no coughs or hiccups at all. Does this sound like a fouled plug or something more? Thanks.

 

[seaway81]

Re: 1999 60 HP Bigfoot Coughs at Idle

Forgot to mention that the air temperature was much lower when I ran it this weekend that it has been run at before, I assume has some affect on the mixture it is getting?

 

[buddym]

Re: 1999 60 HP Bigfoot Coughs at Idle

I recently purchased a tracker with a 60 hp it was sitting for two and a half years there was a warning beeeeeeep continuos that turned out to be the oil sensor in the oil tank I removed all the oil to find at least a 1/3 cup of water in it removed and cleaned oil tank drained all the gas from boat refilled with fresh gas ran on garden hose for a bit then put it in the lake runs good at speed or any rpm range but idle will idle for a bit then sputters coughs stall it will start again and run good but the idle is bad in fact it will not idle for more than a minute I am suspecting dirty carbs