2009 216v w/ EX343 hesitating until engine completely warmed up

[BrianW]

New (to me) Nautique owner this past year and love it! Over the past few trips out this fall, the engine hesitates quite a bit when cold and then gradually improves until it disappears completely. But it doesn't disappear until well after the engine has warmed up and the thermostat has opened and closed several times. It's quite rough for a few minutes driving out of the cove, then slightly rough for another 15 - 20 minutes, then will eventually be perfect and fine for the rest of the day. I've already changed the inline and FCC fuel filters thinking one of those would be the problem. I forgot to check the tube inside the FCC but will (that's my theory). Next time I'm up I plan to replace the spark plugs (1 year / 80 hours old) and wires (original I think) as well, and I bought a fuel pressure gauge to help diagnose if it's fuel related. Any other thoughts folks have? I think it's interesting that it will disappear completely after the engine is REALLY warmed up. I like working on the boat so as long as it's not too involved I'll try most of it myself. Thank you for your help!!

[NautiqueJeff]

Sounds like it is probably just basic tune-up stuff needed -- new plugs/wires/cap, etc. I would look there before chasing a fuel issue. If it was a fuel issue, I would think it would still be present after warm-up.

[NautiqueJeff]

Cap:
https://www.nautiqueparts.com/produc...-efi-ra108009/

Rotor:
https://www.nautiqueparts.com/produc...alibur-motors/

Wires:
https://www.nautiqueparts.com/produc...-pcm-rk120023/

Plugs:
https://www.nautiqueparts.com/produc...sets-platinum/
RP030010
The same plugs can be purchased for significantly less on Amazon here.

Use discount code PND for 10% off on the NautiqueParts links above.

[BrianW]

Thanks I will try that first. And thanks for the part #s and discount code!

[charlesml3]

Yep. My money is on the cap and rotor. I bet they're all pitted up.

-Charles

[BrianW]

Thanks. I didnt realize those were such "wear items" on this year PCM until researching this more. Hope to do it Friday and will follow up.

[BrianW]

Installed new plugs, cap and rotor today. Problem solved! Thanks for the suggestion. Here are pics of the old ones. Plugs looked fine to me. I didnt know such a little amount of corrosion on the cap could make that difference.

[NautiqueJeff]

Glad that took care of it.

[shag]

343 cap's are known to go bad even without noticing anything. And yes any tiny amount of corrosion on the contacts can alter performance. Glad it's fixed!