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Discussion Starter #1
Well, I put my ski's in the water over Easter. they remain in the water (on lifts mind you) for the entire season. they were slow to start up, typical, but got going. went for a quick cruise, but nothing major... ok here's where the problems start...

so about a week ago (last Thursday) we got a horrific wind storm. the wind was so strong on our lake that it raised the water at our end a good 3 feet.

looked out, and the skis were no longer on the lifts, they were floating! :(

needless to say, I acted quickly, tied them off and got the trailer to pull em out. one was a pig to start, they both had an over abundance of water in them from the rough waves. in fact, i had to tilt one near shore, and hand bail out the water before the bilge would kick in... so much water it was covering the battery :(

so, the water level is back down, normal levels and the lifts were repaired and levelled. so i put them back on the lifts today, and on my quick spin around i felt like something was off. its like they lost power.... one more noticeable then the other, maxing out around 8500 RPM (60-65 KM/H) where as last year they can max out around 90KM/h and hit well over 10,000-11,000 RPM. the engine also doesn't have the normal sound it seemed to have when i was in full throttle.

now the lifts are angled to allow drainage, but i am very concerned about this loss of power. i will let them drain and dry out a bit, but might someone have a reason for this loss of power? was it the water logged bilge's?

was hoping to get some advice before i take them in for service to the local dealer and pay way to much money. :(

thanks guys!
 

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Most common cause for power loss on any Yamaha pre-2009 4 stroke (especially the FX models) is fouled spark plugs. I recommend replacing the spark plugs on these skis at the first sign of any power loss. 99% of the time that will cure the problem. This is especially true after the first run of the season. That is when the plugs are most likely to foul. Change the plugs and report back (be careful not to over torque the plugs, they are easy to break..........9 ft/lbs. max torque).

I doubt the water issue is a factor in this case, but let us know if the plug change does not fix the problem.
 

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Discussion Starter #3
Most common cause for power loss on any Yamaha pre-2009 4 stroke (especially the FX models) is fouled spark plugs. I recommend replacing the spark plugs on these skis at the first sign of any power loss. 99% of the time that will cure the problem. This is especially true after the first run of the season. That is when the plugs are most likely to foul. Change the plugs and report back (be careful not to over torque the plugs, they are easy to break..........9 ft/lbs. max torque).

I doubt the water issue is a factor in this case, but let us know if the plug change does not fix the problem.
Thanks for the reply, I will call my local dealer and get some plug.

ok, now not to sound like a moron, but is there a resource one might have on changing these? I have never done service on them. I got them last year with the purchase of my house, and have typically gotten the dealer to do the winterizing, apparently this isn't part of that?

is it difficult to change the plugs... and more importantly where are they located? :dunno:

i have changed many a plug on a car or lawnmower, so not really afraid to change them, but... finding them... hmmmm

also, i supposed i should look up how many i need to purchase. i imagine I should only purchase yamaha plugs?

gosh... i sound like a total newb!
 

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Discussion Starter #4
Ok. Did some work early this AM before work.
Located the 4 spark plugs, and took one out for inspection. It looks used from my eyes, but not terribly. Some 'fuzzyness' around the plug, but otherwise clean.

What I might first try, is removing them all, and lightly sanding them. then taking it out to see if it makes a difference.

I am curious to know why loss of power might be due to a plug? I thougt plugs were only for starting, which i have no issue with, unless a cylender is not firing due to a bad plug. I will do this later today, and report back.

any other feedback is welcome. thanks a bunch!
 

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Discussion Starter #5
THAT DID IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thank you VERY much Ernest T. I would have never thought that the spark plugs were causing this issue. I would have sent it in, had to pay for the plugs and a few hours service charge. That saved me a few hundreed bucks!

Can't thank you enough!
 

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The spark plugs don't just start the ski. They keep it running. The spark plugs ignite the fuel each time a cylinder fires. If you have 1 fouled spark plug on a 4 cylinder engine that = approximately a 25% power loss right there.

On the FX model skis, fouled spark plugs are very common, and THE most common cause for power loss. I've seen a fouled plug cause all kinds of running issues on these skis. Most guys that have worked on that model engine always recommend changing the plugs at the first sign of trouble.

I recommend replacing the plugs, since these small plugs can foul with no noticable change in apparence. They are pretty cheap.

Check the air filter also to be sure it is not wet. Even a 10% saturation of the air filter with water or oil will cause a significant power loss.
 
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