New boat, new member, engine rough idle

[sunbyrned]

Listen to the video from post #16 in this thread. Sounds MUCH cleaner.

Wow! That’s amazing. I use fuel med each time I fill up with gas. Is sea foam for salt water boats only?

 

[Augieol65]

I could be wrong but that last video is what mine sound like out of water without any water in the exhaust box and without water resistance on the impeller. When idled in the water mine sound perfect. How does yours sound in the water at idle?

 

[sunbyrned]

With water flowing through by a hose, it kicks and spits intermittently. Mine have never sounded like post #16 outside the water. I’ll have to listen to them in the water though and see. Will do that today.

 

[FLJetBoater]

I could be wrong but that last video is what mine sound like out of water without any water in the exhaust box and without water resistance on the impeller. When idled in the water mine sound perfect. How does yours sound in the water at idle?

I'll take a video the next time I have it out for comparison...

 

[FLJetBoater]

@gythanks for the responses.

Update on the rough idle and steps taken to correct.

Replaced the plugs on port side engine. I did check plug gap prior to installation. Yes, replaced with factory spec plugs. No discernable markings on the plugs themselves or coil boots.

Fired engine up, same as before. Then, to attempt to see if any of the coils were bad, I unplugged each coil while running for a second or two. I wanted to find if there was a coil that, when unplugged, did not make a difference in sound of the engine, therefore meaning that coil wasnt operating properly.

Both engines, one by one on the coils, affected the idle (made worse), so I assumed it wasnt the coils at fault.

The sound when I unplugged each coil, was similar to the sound of the rough idle, just worse.

In my mind at this point was that it may actually just need a good cleaning of injectors and fuel treatment as some suggested earlier in this thread. Or at least I hoped that was what it was, so, off to the store to get some seafoam. I gave it a heavy dose of seafoam, and saturday on the water I ran the engines pretty good. After a few minutes the engines sounded, well, listen for yourself.

I suppose this means I will run seafoam from now until, well, forever.

How much seafoam did you use to consider it a "heavy dose" ? I am experiencing the exact same noises as you, ran through 1oz/gal but didn't seem to make much of a difference. Wondering if I should run it again with a higher ratio.

 

[Augieol65]

@gythanks for the responses.

Update on the rough idle and steps taken to correct.

Replaced the plugs on port side engine. I did check plug gap prior to installation. Yes, replaced with factory spec plugs. No discernable markings on the plugs themselves or coil boots.

Fired engine up, same as before. Then, to attempt to see if any of the coils were bad, I unplugged each coil while running for a second or two. I wanted to find if there was a coil that, when unplugged, did not make a difference in sound of the engine, therefore meaning that coil wasnt operating properly.

Both engines, one by one on the coils, affected the idle (made worse), so I assumed it wasnt the coils at fault.

The sound when I unplugged each coil, was similar to the sound of the rough idle, just worse.

In my mind at this point was that it may actually just need a good cleaning of injectors and fuel treatment as some suggested earlier in this thread. Or at least I hoped that was what it was, so, off to the store to get some seafoam. I gave it a heavy dose of seafoam, and saturday on the water I ran the engines pretty good. After a few minutes the engines sounded, well, listen for yourself.

I suppose this means I will run seafoam from now until, well, forever.

hey boss quick question were both these videos (rough and smooth) taken while the boat was warm and sitting in the water ie same conditions? Engines sound great in the smooth running video.

 

[Mattr82]

@Augieol65 rough runing video the boat was on a trailer out of the water. Smoother running was in the water.

Motors have performed great all summer. 35 hours and roughly 400 miles of pulling boarders, skiers and tubes, I'm hoping the season doesn't end!