90 hp merc idle coughing

[Tennessee Tom]

when my 90 hp 3 cyl outboard idles in neutral it coughs about every 3-5 seconds. so hard that it looks like someone hit it with a hammer. cant be good. it will go away when I put it in gear and idle. i have had two mechanics and myself adjust the carb screws while running and it clears up the problem for one good spin around the lake and then it is back again. one mechanic had the top carb screw 4 turns out. I put nail polish on the screws and they dont move between adjustments. any help would be appreciated

 

[wilde1j]

Re: 90 hp merc idle coughing

Running too lean will cause what you describe.

 

[Bob H.]

Re: 90 hp merc idle coughing

4 turns out is a bit extreme. Split and clean the carbs.

 

[cwilt]

Re: 90 hp merc idle coughing

where i come from its called a lean sneaze

 

[laker925]

Re: 90 hp merc idle coughing

Sounds like Tn talk...from there too!<br />Tom -what area?

 

[Tennessee Tom]

Re: 90 hp merc idle coughing

I am from the cookeville area. halfway between nashville and knoxville. thank you for your replies