Rough Idle & Apparent Loss of HP - 2008n SAN 230 w/ 409

[BKinSoCal]

I have a 2008 SAN 230 with the 409. It is idling rough and loud. In addition, it feels like there is HP missing when accelerating. There are are no issues with it starting. It doesn't sputter when accelerating, just feels sluggish. The plugs were changed 120 hours ago. There are 550 hours on the engine.

I have an idea of what it could be, but I would love some input from the experts on PN. Any and all help would be appreciated!

Thank you.

Brian

[shag]

Could be several things. I would bet you need both fuel filters changed. Also, if that motor is anything like the 343, it goes through spark plugs (imo) abnormally fast. I would also replace the distributor cap. They can go bad and cause your problem.

[tcaviness]

If you had the fuel filter changed recently, check to make sure it is tight. I had the dealer replace mine once and we hit the lake with the same problem. That’s where we found our problem. Maybe it is contributing? FWIW

[BKinSoCal]

Thank you, Guys. My belief was it was possibly the fuel filters. I already have new ones in hand, they just need to be replaced which will happen later this month. I didn't replace my original spark plugs until 420 hours. I'm hopeful that isn't the problem again. It definitely isn't running like it was when I needed to replace them before. The distributor cap was something else I had heard so we'll change the fuel filters and see how it runs and then move to the distributor cap is necessary.

Thank you again. PN has so much knowledge available and everyone looks out for one another in the Nautique Community!

Brian