View Full Version : Running Rough at Idle

06-15-2012, 11:34 PM
Hey all, very new to the boating world, this will be my first full summer as a boat owner! Love it already!! cant wait to get out everyday!

I have a 98 outback and have noticed lately that it runs pretty rough at idle, seems to almost want to stall out. May seem pretty simple fix but I have not a clue where to start. I can say that the gas is not from a marina if that means anything. Any help/advice would be awesome.

Just wanted to say that this forum is awesome, tons of info and cool projects. First time on here and it has been about 2 hours now!

Thanks again for any help!

06-16-2012, 08:38 AM
Without knowing anything at all about your boat. When was the last time it had a tune up? oil/filter, plugs, distributor cap/rotor, fuel filter, and timing set are all items to get done. If that has been done and you still have issues, then time to look at the carb. It may need a cleaning or rebuild.

That is where I would start.

06-16-2012, 09:47 AM
Ya the only thing that I know for sure is the I have changed the oil before the start of season. I will try and contact previous owner to see if he has some answers and start checking that stuff along the way. thanks for the help!

06-16-2012, 12:30 PM
Another thing you can do is go ahead pull the plugs, look at them if there dark in color or anything corroded replace them. As for Wires if there bad you will get missing which is much different then rough idle. The motor will shake badly at idle, or when you give it power you will hear a dead spot in the hum or burble of the exuast.

For the Carb, a quick way to see if it needs cleaned and tunes is while its running rev it up to about 1500 and spray Carb cleaner in it but not so much you stall the engine so be carefull. If it runs better after then you need a carb rebuild.

What RPM is it idleing at? Should be around 700-900 max. If its really low it will run rough as its trying to just stay running. Sometimes people will dial the idle real low to make the engine sound like its got a big cam when it doesnt.
You should have an idle screw on the throttle at the carb, you can turn this in slightly and you will see it pushing on the idle. This is seperate from the feed screw < cant recall proper name > but it deals with Off idle fuel mixtures.

06-16-2012, 10:11 PM
Thanks I will check Them, easy fix if they are bad. Ya no shaking in the motor. I was on it today and checked the rpm's at idle and it was about 800, so pretty good there. It ran well until the end and we cam back to pull it out and it seemed to be acting up again. I will check everything that you all have mentioned.


06-18-2012, 05:41 PM
My 2006 Outback has been like that from day 1, dealer has no clue why. Tried additives, no additives, tune ups, just runs rough then stalls. Too bad because everything else about the boat is awesome. Bummer.

06-20-2012, 01:39 AM
Hi gammapark, sorry to get off topic, but in 2006 Holley had some bad castings in their carbs. I don't know if you have a carb or EFI, but I've seen the inside of a carb on an 06 LSV that looked like someone filled it with hydrochloric acid. Check it out, a new carb may be the answer to your problems.