pgh_flytier
Avid Angler
- Total Posts : 249
- Reward points: 0
- Joined: 2004/07/27 08:13:45
- Location: North Pittsburgh
- Status: offline
Rough idling outboard
I have a 9.9 4 cycle Merc that is only a few years old with very few hours of use. It is idling so rough I have to keep the choke on whenever it is at low speeds, no matter how warm the engine becomes. It seems to run pretty good when it is on higher speeds. In order to avoid a costly repair does anyone have any suggestions what might be causing this? There is fresh gas being used, the oil and lower unit fluid was changed at beginning of year. The squeeze bulb on the fuel line never seems to get hard. should this be hard when the engine is running. Anyone have any suggestions on what to check?
|
pghmarty
Pro Angler
- Total Posts : 5951
- Reward points: 0
- Joined: 2004/12/05 01:02:33
- Location: Bradford Pa then Pittsburgh
- Status: offline
RE: Rough idling outboard
2011/07/12 11:44:19
(permalink)
Tighten carb to motor and check fuel lines+bulb
|
SlipperySmitt
Moderator
- Total Posts : 404
- Reward points: 0
- Joined: 2008/10/14 08:57:33
- Status: offline
RE: Rough idling outboard
2011/07/12 12:19:16
(permalink)
As Marty said, also check/change the plugs. I would only recomend NGK's. I have a 99 Merc 4 stroke, most cold blooded "B" of a engine I ever owned. Best boat motor for fuel use I ever had though. Also try some Sea Foam, may have a gumed up or dirty carb or possibly some mositure. Smitty
post edited by SlipperySmitt - 2011/07/12 12:21:02
|
snydje
Novice Angler
- Total Posts : 71
- Reward points: 0
- Joined: 2010/12/26 21:47:42
- Status: offline
RE: Rough idling outboard
2011/07/12 13:22:32
(permalink)
I had the same problem. It was almost like it was running on only one cylinder. I changed plugs and ran some fuel cleaner through and it cleared up. I actually put a little fuel cleaner in the squeeze bulb and re-tightened all hose connections. It smoked like h*ll when I first started it but it cleared right up. Been running fine since. The alcohol additive in today's gas is extremely corrosive and gums up very quickly....so I have been told.
|
eyeassassin
Expert Angler
- Total Posts : 847
- Reward points: 0
- Joined: 2010/05/19 22:32:21
- Location: SW Pa
- Status: offline
RE: Rough idling outboard
2011/07/12 13:34:43
(permalink)
make sure you are using a stabilizer in your fuel
REMEMBER HOW MUCH FUN YOUR FIRST BIG ONE WAS. TAKE A KID FISHING
|
northparklake2
Avid Angler
- Total Posts : 143
- Reward points: 0
- Joined: 2007/04/13 08:42:52
- Status: offline
RE: Rough idling outboard
2011/07/12 14:24:59
(permalink)
Use Stabils marine formula fuel stabilizer and ethanol treatment every time you fill up. but for the current problem i would do as stated before to use seafoam and change the plugs. check all lines and tight all bolts. sounds like a possible air leak causing it to run lean
|
pgh_flytier
Avid Angler
- Total Posts : 249
- Reward points: 0
- Joined: 2004/07/27 08:13:45
- Location: North Pittsburgh
- Status: offline
RE: Rough idling outboard
2011/07/12 15:10:42
(permalink)
Thanks for all the advice. I'll give everything a try and see what happens.
|
hiclassHilbilly
Pro Angler
- Total Posts : 1052
- Reward points: 0
- Joined: 2009/01/07 22:46:38
- Location: Glendale, pa
- Status: offline
RE: Rough idling outboard
2011/07/12 15:11:24
(permalink)
I had a similar issue and my carb ended up being way out of tune. I had the local shop retune the carb and replace all fuel lines and they had to replace the fuel connector on the motor housing because was gummed up and not letting enough fuel through to max my RPMs and it was choking the engine at idling speeds.
"A Homewood man led police on an hourlong car chase that ended with a crash injuring three officers. "The car was driving itself," Wright said. "The car has a GPS. It's a Lincoln Navigator. They drive themselves. I wasn't running nowhere."
|
dr walleye
New Angler
- Total Posts : 9
- Reward points: 0
- Joined: 2010/06/30 17:44:22
- Status: offline
RE: Rough idling outboard
2011/07/23 11:37:59
(permalink)
try using lucas fuel injector cleaner.i use it in mine all the time and have never had a problem with it
|
deepcreek bound
New Angler
- Total Posts : 32
- Reward points: 0
- Joined: 2002/01/23 20:25:26
- Location: Buffalo Mills, Pa
- Status: offline
RE: Rough idling outboard
2011/07/27 09:51:33
(permalink)
Id take the carb off an clean all your jets....sounds like they are clogged. and as said earlier use marine stabil. with every fill up after that. if that bulb isnt geting hard, time for a new one. DB
|
pgh_flytier
Avid Angler
- Total Posts : 249
- Reward points: 0
- Joined: 2004/07/27 08:13:45
- Location: North Pittsburgh
- Status: offline
RE: Rough idling outboard
2011/07/27 10:17:22
(permalink)
Thanks for all the advice. I haven't had a chance to take it out since my first post, but I did get new plugs. I use regular Stabil, but I will switch to the marine stabil with the next tank. I don't feel confident enought to clean out the carb, but I might look for some kind of cleaner I can add to the gas. Can the bulb be changed or do you have to buy the whole fuel line? I leave mine plugged into motor and tank all the time, not sure if that is what you are supposed to do.
|
Rick Bass
New Angler
- Total Posts : 32
- Reward points: 0
- Joined: 2001/04/05 22:24:42
- Status: offline
RE: Rough idling outboard
2011/07/28 06:04:53
(permalink)
Replace the end of the fuel line, the part that attaches to the engine.It can be purchased at walmart.They sometimes go bad.Happened a few times to me over the years.They sometimes leak air around the fitting, and that is why the bulb won't hold the prime.
Good Luck
RB
|
hotrod53
New Angler
- Total Posts : 35
- Reward points: 0
- Joined: 2011/07/17 10:35:04
- Status: offline
RE: Rough idling outboard
2011/07/28 20:50:27
(permalink)
I would remove the carb and clean it, these carbs are not complicated and even the rebuild kits are cheap. I suggest that you disconnect your fuel line and run your motor out of fuel every day when you finish. This gas today loaded with ethanol is bad stuff. On my 50 hp, before I did that, my needle valves stuck 3 times, not once since. The ethanol swells the rubber tips on the needles and makes them stick in the seat.
Seafoam, StaBil, Ring Free, using one of them is a must, you need to keep that fuel stable. If the squeeze bulb is not getting hard, either the check valve is going bad in the ball, your needle valve isn't closing off meaning bad needle/bad seat/float issue, or you have a leak in the fuel line.
|
psu_fish
Pro Angler
- Total Posts : 3192
- Reward points: 0
- Joined: 2008/08/28 22:37:11
- Location: PA
- Status: offline
RE: Rough idling outboard
2011/07/28 21:02:05
(permalink)
|