Just had my 225 Pro XS serviced - new plugs, filters, etc. Runs great with any gas at all but I am getting a miss at idle. Taking it back to the dealer tomorrow but curious if anyone knows what would cause this. Don ? I am adding both Quikcare and Quikleen to the tank at 1 oz per 5 gal.
Leonard W. Little
Grand Junction, CO
2005 Champion 198
Correct plug gap is critical on these motors. If im not mistaken plugs ordered from mercury are pregapped but any other distributor sends em out at .035. I would start there
IF ITS BLACK ITS ON THE BACK!!!
Plugs ordered from Mercury are NOT pre-gapped for this application.
You must gap the plugs to .044" (very, very carefully, so as not to damage the electrode, or crack the surrounding porcelain).
IF idle problems persist.... drop me an email with your phone number (or give me a call). I may have some other pointers, depending on your engine's serial number.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
You are having all kinds of problems I see. I switched to 89 octane. That helped. I also had the same problem after a plug service. Take the cowlling off and make sure every spark plug wire is on good and tight. I had one that did not get put on good from dealer and it was an intermittent miss at idle but seemed to run ok other than that.
Don thanks for clearing up the gap on the plugs from merc. I thought merc came pregapped ( as per instructor last year) but i guess the only difference in ordering from merc is the 1 year parts warranty ( which is more than enough reason to buy from them on an optimax)
IF ITS BLACK ITS ON THE BACK!!!
Don't feel bad, Ryan. There was a point at which we were being told the "-11" (.044" gap) plugs would be available as a replacement part.
They were even assigned a part number.... but it never materialized. Latest news has been that they will NOT be available as a replacement part (use the IZFR6J plugs, and gap them accordingly).
Back to the original question.... if the regap of the spark plugs, and/or use of 89 octane fuel does not improve idle quality, drop me an email (or give me a call) for at least one other "pointer".
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Interestingly I did not have this problem before replacing the plugs - It did vibrate at fast idle a lot more before though. That problem is not as bad. I run 89 or 91 octane - marina near me on Lake of the Ozarks claims they have 91 with no ethanol.
Leonard W. Little
Grand Junction, CO
2005 Champion 198
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