Starboard engine running rough

[Gym]

I would still go for spark plugs first. You can still keep the ones you removed as spares if the new plugs don't help. Do you get this vibration while running that engine on the trailer with the hose running? If you only get it on the water I would consider pulling the pump assembly. It's only a 30 minute job and will give you a good look at the impeller & pump. Also pull the rear cone and check the bearing for water intrusion.

 

[haknslash]

Next time I'm down in Ttown we can try to meet up so you can get a second Yamaha owner opinion.

 

[Augieol65]

Ok, after spending several hours on Lake Eufaula the last couple of days (man, it was ROUGH), I’ve decided that my problem is probably not plugs nor cavitation...it feels more like a vibrations at idle (or just above) on the starboard engine. Next time out, I’m going to open the engine hatch while idling and see if I can tell what’s going on. Man, I really need to get someone more knowledgeable on my boat to help me diagnose this (yes, that’s an open invite!).
I can’t tell that there’s any performance drop off at all. It’s really just more of an annoyance (and fear of potential issues) than anything else.
And, back to Eufaula...the weather was gorgeous most of the time. The winds that made the lake so rough also made the heat so much more tolerable. I forgot just how shallow this lake is in most spots. As big as it is, most places are 10’ or less outside of the channel. You also really have to watch for logs and submerged stumps. I grew up here...I just forgot. I’ve been spoiled by the deep and clean (albeit much smaller) Tuscaloosa lake.

@Ghinson95

Hey boss you ever get this figured out? I’m battling the exact same thing. Only at the lowest idle and no wake 1 maybe 2 the starboard engine is tougher than port. Checked all the things people had listed on here and didn’t know if you figured it out. Like you said more of an annoyance and I think my wife is me sick of asking her “isn’t it louder?” Haha

 

[Ghinson95]

@Ghinson95

Hey boss you ever get this figured out? I’m battling the exact same thing. Only at the lowest idle and no wake 1 maybe 2 the starboard engine is tougher than port. Checked all the things people had listed on here and didn’t know if you figured it out. Like you said more of an annoyance and I think my wife is me sick of asking her “isn’t it louder?” Haha

Unfortunately, no. I've just been running it and it doesn't seem to affect performance at all. I haven't tried changing the plugs yet. Have you?