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Starboard engine running rough

Ghinson95

Jet Boat Lover
Messages
18
Reaction score
11
Points
82
Location
Tuscaloosa, AL
Boat Make
Yamaha
Year
2017
Boat Model
Limited S
Boat Length
21
2017 212...A couple weeks ago, I got in a little bit of grass on lake Tuscaloosa. I cleaned a very little bit out of the starboard clean out port, but that engine (impeller, really, I guess) has run much rougher than the port engine at idle. I’ve reached in and felt around as much as I can and don't feel anything, but that engine just does t seem as smooth as the other. It’s very noticeable if I run each engine separately. Once I throttle up, everything seems to run fine and it’s not noticeable.

So, what to do? Should, I pull the starboard jet to see if there’s something in there I’m not feeling? If anyone is going to be on Lake Tuscaloosa this weekend, I’d love to get a second opinion. Maybe I’m just imagining it, but I really don't think so.
 
@Ghinson95. You may still have a twig or piece of plastic jammed up in there. If you're still in the water you may want to try the reverse maneuver where you put your boat in reverse, at a moderate speed, pull the lanyard to kill the engines then quickly put both dead engine throttle levers in the forward position. This allows water to reverse flow through the intakes to flush out most debris. If you're on the trailer get under the boat to get a good look at the intake. I'm sure you still have something in there that wasn't accessable through the clean out ports. While under the boat check the calling around the intake grates to make sure none is missing. Calling that is missing can cause cavitation resulting in a vibration.
 
Agree on the reverse method. Possible you have something wound around the driveshaft close to the impeller that's going to be tough to see from the back. Might be throwing off the balance at lower RPMs. Agree to put it on the trailer and look up through the intake grate.

Might be time to pull the pump and have a close look.

-Greg
 
I agree with the others, sounds like you still have something up in there. It only takes something very small to cause an issue. Even something like fishing line or a small piece of plastic or trash. I more than likely won't be on Lake Tuscaloosa today but if I do head there I will let you know and we can meet up. I would pull the boat out, look real good in the jet pump and from underneath looking through the intake grate. Something has to be up in there. If all else fails pull the pump. @Bill D did it at the launch there when he sucked something up. Shouldn't take you long unless you run into the issue @AboveTheBest did recently with his.
 
My reverse move is a little different I don’t use lanyard I just go in reverse then throw throttles in forward and give it a little thrust and back and forth between forward and reverse a few times and never had a problem blowing stuff out.
 
I meant to try the reverse move yesterday and just forgot. It’s on the trailer now, so I’ll get underneath. I’m with y'all....I'm convinced something is in there. Hope I can get it without pulling the pump.

Thanks for the advice!
 
My reverse move is a little different I don’t use lanyard I just go in reverse then throw throttles in forward and give it a little thrust and back and forth between forward and reverse a few times and never had a problem blowing stuff out.
This works a lot of times, but there's an important difference between this and what @Gym mentioned. In the first mentioned method, you're actually forcing water back through the nozzles and out the intake grates, opposite of normal function. With what you described, you're just moving the buckets with different levels of throttle. It may still work, and I've done it, but you're only moving water in the normal direction.
 
Well folks, I crawled underneath and didn’t see anything. So I pulled the pump. I learned two things:
1. It’s hot as @#&& out today
2. There’s not a darn thing in there. Clean as it could be and impellers looked perfect.

Pulling the pump was easier than I thought it would be. Only issue was the lateral thrusters made it a pain to take that 1 bolt out that it uses. There was not enough room to turn the wrench very much. Probably would have been faster to drop the lateral thruster, but I’m stubborn.

Not sure what to do now. I’m gonna put in at Rock Quarry around 5 today if anyone’s going to be around. I’d love to let someone else hear it and get a second opinion.
 
Did you check you silicone to see if any was loose
 
Yea, and that could be it I guess,maybe. I pulled off a couple of very small loose pieces, but nothing big at all. Feeling around inside feels pretty much just like the other side. I considered trying to scrape off any excess in there but didn’t know of I should or not.
 
I had strips that were there but not sticking
As I would increase rpm the suction would pull the silicone away from the hull until I nursed it thru that rpm zone then the cavitation would go away
Just looking at it it looked fine. But if I pulled on it it would pull away

Just something for you to check


.
 
Have you tried changing the spark plugs?
 
Yea I'd change the plugs if you haven't already this season.
 
I think plugs will be next. Do y’all change every season? I did not change mine.
 
Yup I change mine every season. Cheap insurance as these engines can be a little finicky running less than perfect plugs.
 
Roger that. Guess I’ll start searching for plug threads, lol.
 
I've migrated my plug changes from every year to every other year. We do 35 - 50 hours per year. But a plug change is cheaper than bringing it to the dealer.
 
I buy mine from partszilla https://www.partzilla.com/product/yamaha/LFR-6A000-00-00. Good prices and super fast shipping (their east coast distribution center is in Albany, GA) so I usually get my parts in 2-3 days.

BTW they have the best prices on the net for the Yamaha oil change kits ;)
 
Last edited:
You just saved me some searching. Thanks!
And yes, it’s definitely worth changing plugs before a trip to the dealer, although I think I’m still under warranty. I just don’t have one close nor do I want to lose my boat for no telling how long during prime season.
 
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.
 
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