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Discussion Starter #1
I posted this on another thread, but figured I'd ask in my own:

After 10-20 mins usually top out around 40 mph. Had carbs rebuilt 2 years ago, ran great till last year... now the above issue. Only 10-15 hours on it since the rebuilt carbs. 2 guys w/ over 30 years of experience on 2 stroke engines gave me this advice. What do you guys think:

Try to empty tank (could be water getting into the carbs)
Run 93 octane (said I should always run this)
Use stabil fuel system cleaner (not just the stabilizer) Said it works great. It will smoke like hell, then should run awesome if there is dirt,etc...
get a water/fuel seperator into the fuel line

Any thoughts from the experts on here? He said try all this... should work. The carbs shouldn't be that gummed up after 2 seasons now (probably on 10-15 hours since the rebuild). Also, much cheaper to try this, than get a $1000 rebuild again.

Any help is appreciated!
 

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Water in fuel could be an issue if it has set for a period of time with a partially filled tank due to condensation. If it is going to be sitting for a while, fill the tank (reduces space for condensation), and add fuel stabilizer like Sta-bil.

Unless your engine is knocking (pre-detonation), running higher octane fuel will be of no benefit. It does not increase power, speed, etc..

If you have put only 10-15 hours on the ski in 2 years, then it has been sitting with fuel in the carbs for long periods of time, which is exactly what causes them to get fouled up.

You might try running Seafoam additive through to see if it will help clean out the system. Yamaha also makes an excellent product called Ring Free (and a new formulation called Ring Free Plus) that is proven to remove carbon and deposits in 2 and 4 stroke engines. I run it in my waverunner and boat outboard in each tank of gas. Its good for fuel injected and carburetor engines. Fuel additives may or may not be able to free up a fouled carb.

Also you can clean and rebuild the carbs yourself for around $50 or less per carb for the rebuild kit. Just cleaning them is only a few $$, because you only need to replace a few gaskets. Its not that hard to do, but is time consuming. Check out this video from SBT: http://www.shopsbt.com/video/protip7high.wmv
 

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Yahmaha for the last 3 years has been insisting that people drain tanks to empty and treat what is left over in systems containing ethanol fuel. Ethanol is trouble every where it is used. Especially when mixed into non ehtanol fuels, which can still be purchased in Maryland. If you sit there and say I am full shit, than good luck my friend. One more tid bit of news with ethanol the octane level drops. Yes that is also correct. I have a 23 Nova with 650 HP ZZ502 block. It f___n drives me nuts because I always worry about detonation damage. I like the 108 octane boost for simplicity. Hopefuly it is not snake oil. Best insurance I feel is the old school Sunoco Race fuel "old purple" 115 octane. I put a gallon per 12 gallons. Smells great in the exhaust fumes. Yeah I have sniffed to much but still kick'n. Do what ya like Chaaaaaaawwwlie.
 

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Discussion Starter #4
ok thanks guys.... i ill check the video and see if i can clean/rebuild myself if need be.

I might try the yamaha ring free you mentioned first.

Also, I think my guy was recommending 93 octane because it has more additives, rather than suggesting a power boost.
 

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Hi Usually if your topping out at 40 I would say maybe your running on 2 cylinders. First thing you need to do is check compression, make sure you are getting fuel and oil, if not mixing no broken oil lines. After about a half hour or so probably less of not running good your piston and most importantly your cylinder will be done. I would shut it down and look into it before major damage occurs. Compression test will tell you alot. If that check out ok, which is simple test, then I would check into carbs.
 
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