1988 merc 80hp rough idle

[myboatisbroke]

a guy I know is having issues with his outboard(1988, 80hp), It starts up, midrange to W/O runs great, but runs rough at idle. He said if he hits the choke, it will run good, until coming back down to idle from cruising speed. I'm leaning toward an air leak somewhere, possible bad fuel pump, or maybe plugged pilot jet? I don't have the boat in my barn yet(tomorrow maybe), and thought I might get a head start on diagnosis with this thing. According to him, he has spark on all 3, and compression is 120 on all 3. Thanks

 

[Maxz695]

Re: 1988 merc 80hp rough idle

carbs may need needle and seats Float level air mixture adjustment yes check all fuel lines. A rebuilt fuel pump is always a good thing

 

[myboatisbroke]

Re: 1988 merc 80hp rough idle

well got the boat at my place finally, it took about five seconds to find the fuel primer bulb pissing right out of it. I'll replace it tomorrow and see what happens then