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Discussion Starter #1
I have a 2003 FX140 that has been running poorly all summer. After reading about overfilling the crankcase being a problem, I checked the oil and it was overfilled so I pumped out enough to get it down to the full mark. I ran it and it was still slow, about mid 30's and no more than 8,700 rpm. I then removed the aftermarket air cleaner to see if it was that and it didn't improve at all. Next I bought some new sparkplugs and went to change them but my 5/8 spark plug socket won't fit down through the head to get to the spark plugs. It's a craftsman. Do I need a special thin walled socket for this job?

In addition to the above problems, it won't idle, and the last time I tried to ride it, it wouldn't start. Any suggestions would be greatly appreciated.
Thanks,
JimBinMI
 

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Overfilling the oil causes 2 common problems on this ski:
1. It causes the spark plugs to foul
2. It back flows onto the air filter

Fouled plugs may be hard to see visually, but is THE most common reason for poor running on the Yamaha 4 strokes.......always replace the plugs first when you notice a performance decrease.

Check the air filter. It should be clean and dry. Even a little oil on it will significantly reduce performance. Replace if needed

The spark plugs are standard size, but you will need a thin socket to get to them. The spark plug elements are only 10mm and are fragile, so be careful when replacing not to over torque (Yamaha recently lowered the recommended torque to 7 ft.lbs (down from 9). If you turn them too hard you will snap them off.

I'm betting that new plugs will cure your problem.
 

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Discussion Starter #3
Thanks Ernest T.

Thank you for replying.
I stopped by my local Yamaha dealer this afternoon (I bought my ski used from an individual) and spoke with the service coordinator, he went into his office area and came out with a long plug wrench, we took it over to parts and sure enough it fit my plug. He said there you go. I said how much and he said just put it in your pocket and walk out, it's an extra one that I had laying around here.
I haven't spent a penny in this store but you bet I will in the future!
Thanks for your info on torque.
I'll put in the new plugs tomorrow and see how she runs! :thumbsup:
 

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Discussion Starter #4
Back to "Normal"

OK, so I changed the spark plugs (even the Yamaha plug wrench was a snug fit to get to the spark plugs). The plugs were very fouled, black.
I rechecked the oil level and it was still above full, so I removed some more oil until it showed just below the full mark.
Lowered it off the lift, started it up and it actually idled!!
Took it around the lake several times and it ran like it used to.
RPM's were back around 10,000 and it registered 50+mph on the speedo.

Thanks for the great assitance!
JimBinMI
 

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Discussion Starter #6
Thanks!

Thanks Ernest T., really appreciate your knowledge and willingness to share it.
JimBinMI
:thumbsup:
 
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