1990 Mercury 75hp Outboard - Won't idle when engine is warm.

[Brian A]

Hello,

I recently got a 1990 Mercury 75hp outboard motor that had been sitting for a number of years. I changed the fuel filter, fuel lines, spark plugs, and oil lines. When cold it starts very easily and idles great. I get good power out of the motor, and it runs very smooth. I was out for the second time this past weekend (which was actually the longest I have used the motor since I got it), and I noticed that after the motor warmed up (running for a good 20 minutes), when I shifted back to neutral it would stall out. Upon trying to restart I had to use the fast idle lever to get it to start. The motor would stall very quickly when I pushed the fast idle lever back down so I could shift into first gear.

Anyone have any idea what the problem could be and how I should go about fixing it? Is there a simple adjustment, or should I rebuild the carbs?

Any help would be appreciated!

 

[Charlie61]

Re: 1990 Mercury 75hp Outboard - Won't idle when engine is warm.

I do not know if your that a enrichen vale mine a 1983 115 and the enrichen vale was stopping mine from running at all I think mine was sucking air becase it has a little gas in top of it. then I tured the top by the sping the idle would change. hope this helped by the way mine set for 8 years before I ran it the year

 

[Dave1027]

Re: 1990 Mercury 75hp Outboard - Won't idle when engine is warm.

the fast idle lever to get it to start. The motor would stall very quickly when I pushed the fast idle lever back down so I could shift into first gear.

Anyone have any idea what the problem could be and how I should go about fixing it? Is there a simple adjustment, or should I rebuild the carbs?

Before you rebuild the carbs you need to try a sync and link adjustment procedure which is basically timing and carb adjustment.