3.0 l Merc runs rough in rough water

[bwright]

I have a new to me 97 sea ray with a 3.0liter 4cyl. merc. The boat was stored for quite a while about a year and half. I put in new plugs and new fuel with mercs fuel system cleaner. When running in rough water the motor feels like is going to stall out. It stalls out for a second and then kicks back in again. If you bring it back to idle it won't want to run to well, it coughs. At this point, it sometimes will either stall or run ok. If it stalls, it starts really hard. Calm water it runs great!!! It only acts up in rough water. I pulled water skiers all day today!! I would really like to run the boat in all weather.

 

[biloxiriver]

Re: 3.0 l Merc runs rough in rough water

I just started having this type of issue with my inboard 302. I am inclined to look towards a carburator problem, or a partially obstructed fuel filter; my problem seems to be on initial acceleration, engine idles good and runs at high rpms good.

 

[pingjockey]

Re: 3.0 l Merc runs rough in rough water

Sounds to me like there might be some water in the tank. You said new feul but not if y ou drained the tank. Is the a fuel/water separator. Change it out if so. If not install one.

 

[bwright]

Re: 3.0 l Merc runs rough in rough water

Filters checked out ok. Still runs fine in calm water but horrible in rough.

 

[akriverrat]

Re: 3.0 l Merc runs rough in rough water

water in gas stirred up by rough water. same for water seperator that is nearly full of water. will run fine till you hit chop.

 

[bwright]

Re: 3.0 l Merc runs rough in rough water

So far I have changed the filters. When I pulled the holder and dumped it into a glass there wasn't any water in the fuel that I could see. Any other quick things to check?

 

[akriverrat]

Re: 3.0 l Merc runs rough in rough water

if not water in gas...electrical? a loose wire on my ignition switch caused similar symptoms. start checking connections including harness plugs for loose and/or corroded connections.

 

[bwright]

Re: 3.0 l Merc runs rough in rough water

well found out what the problem was!!! I was a bad spring in the anti-siphon valve. Boat runs great in all water now!!