[Goob13]

The ski will run great, topping out around 52 mph, then all of a sudden it will bog down and I can't get over 30-35, then just as quick it will feel like a turbo kicks in and it will jump back up to full power..

Any ideas on what could be wrong?

 

[Ernest T]

As a first step, I'd recommend replacing the spark plugs. A bad plug can cause all types of running problems on these skis. I highly recommend this as a first step with any Yamaha 4 stroke when there is an issue with loss of power. New plugs will fix 95% of the problems.

If you try new plugs and still have a problem, I'd suspect a dirty fuel injector. As a first step get a bottle of Yamaha Ring Free Plus, and run it through with a fresh tank of fuel. I'd double the dose (use 2 oz./10 gal. fuel) to see if this will fix the problem. If it is still running bad after this, you may need to remove and manually clean the fuel injectors (they have a screen filter that occasionally gets clogged).

 

[BIGtymSKI]

The ski will run great, topping out around 52 mph, then all of a sudden it will bog down and I can't get over 30-35, then just as quick it will feel like a turbo kicks in and it will jump back up to full power..

Any ideas on what could be wrong?

Same thing happened to me this weekend (2004 Yamaha fxho cruiser) the ski wouldn't go past 8000rpms and didnt go past 30-35mph, should be the spark plugs. I changed them and shes running perfectly fine now.