Q: WOT RPM variation

[carl sastram]

I just bought a 22 Sea pro w/a with a 2005 yamaha FX 150 four-stroke. The motor starts and runs excellent, but Im experiencing a significant variation in RPM and speed at Wide Open Throttle (between 4800 and as much as 6000). Is this normal. Am I dropping a cylinder intermittently? I am running it in a tidal river.

Thanks for any help.

-Carl

[boats.net]

Is the prop cavitating or hub slipping on prop? Try a new set of spark plugs and check fuel filters.

[carl sastram]

I'm getting some cavitation, but only when I throttle down. I think that's normal. Not sure how to tell if the hub is slipping. I put new plugs in already. I'll check the fuel filters. Thanks.