my brother has a 2008 300xs with 33 hours on it..went out yesterday fishing and coming back in it wouldnt turn but 5600 rpm @ 95 mph.. last week it was turning 6100 with the same prop,load etc etc. changed the fuel filter today and still wont turn but 5600rpm...no alarms,nothing on the smartcraft gauge...pulls like crazy till about 5300 rpm and then its like it falls off...any ideas??????????????? thanks
Start with the basics- Compression, Spark (test), and Fuel Pressure/Flow tests (will include air pressure test).
Don't forget to inspect the spark plugs.... the Opti's do a nice job of "masking" a fouling (or cracked) spark plug.
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
Is it possible to see the crack or do you have to count that the crack is hidden and change the plug anyway.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The Swede »</TD></TR><TR><TD CLASS="quote">Is it possible to see the crack or do you have to count that the crack is hidden and change the plug anyway.</TD></TR></TABLE>
I find them relatively easy to spot- look for any line (in the white porcelain surrounding the electrode) that runs "lengthwise". Normal burn marks/spots will run "sideways".
I replace ANY plug with lengthwise lines or marks... usually, if cleaned and observed under bright lighting with a magnifying glass, you can actually see that the line is indeed a "crack".
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
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