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Max Online: 36273 @ 01/23/13 02:34 PM
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#10972878 - 07/12/15 09:37 PM '04 Merc XR6 poor idle issue
bell0347 Offline

Registered: 01/02/12
Posts: 71
Loc: Montgomery,TX
I've owned this motor for a year and a half or so now and it has always ran like a top. I recently ran some sea foam through it, changed plugs, water pump, etc. and it has been running great since. Saturday I was on Fayette and that morning it cranked on the first try and idled for several minutes just fine. As the day progressed and it got hotter and hotter, air temp was 97 I believe and surface water temp was 93, the motor seemed to not want to idle. When I goosed it and jumped on plane it'd run fine but then wanted to die if you didn't use the high idle. Is this related to the temps? I put 89 octane in it that morn, would 93 help it run better in the heat? To my knowledge this motor has a smooth idle feature which lowers compression via some sort of special porting. I think it lowers compression while idling. I'm thinking that the less dense fuel/air charge with lower compression at idle may cause it to run rough until the rpms bump up a little. What say you?

#10973222 - 07/13/15 07:36 AM Re: '04 Merc XR6 poor idle issue [Re: bell0347]
TLW Offline
Extreme Angler

Registered: 11/16/06
Posts: 1974
Loc: ft worth
those are called "idle relief slots".. pretty common on most V6's since tha late '80's.. really won't effect idle quality other than they're purpose..

first thing i'd look at is fuel pump diaphragm.. then all bleed lines.. check all CDM's at idle.. could have some junk that mighta broke loose in tha carbs with tha "treatment".. there is also a "thermal air valve" in tha starboard head that has some control on tha idle circuit that could be suspect also.

being an "electronic motor" could be tha ecm (control module) actin' strange...justa few things that can be suspect..

#11026430 - 08/07/15 07:45 AM Re: '04 Merc XR6 poor idle issue [Re: bell0347]
Skeeter-Blue Offline

Registered: 12/31/09
Posts: 180
Loc: North Texas
Since it happened after getting fuel at a different location, I would drain some fuel into a jar and check for debris and water before going nuts with the mechanic. You can also get lots of water and debris in your fuel it the tanker is filling the tanks when you are filling yours.

I would also inspect the spark plug Wires, my Black Max idles like [censored] sometimes, when the gas is bad or old, or when a spark plug wire is not seated all the way. You can test the Wires by putting an old AM translated radio near the plug Wires. Way old school.

I run seafoam at one can per 14 gallons all season long to condition fuel and reduce carbon build up....good stuff.
95 Skeeter 150ZX w/ Merc XR6 150
Ocean Kayak Prowler 13
59 Yellow Jacket w/ Merc 50


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