Loss of Power maybe Fuel Pump?

[dusman2000]

Okay i'm new to this forum I've had my 2013 SX190 for 2 years. Let me start off with this. Last year 2 times while out the boat wouldn't start. As if the fuel pump was not working. It finally did start and it didn't happen again all summer after those two instance.

This year we take the boat out, And at first seemed okay but almost felt like it had bad gas. The boat had half a tank in it when i put it away in november I only run 91-93 oct. and 99.9% sure i had non ethonal in the tank before i put it away for winter. I added 15-20 gals that dat before we went to the lake of 93 oct with Ethonal because I couldn't find Non that was 91 or 93 for some reason at the same place i had used last summer.

Boat started easily as it always has. We take off and boat seems to be running okay we ran for about 10 mins we shut down for a few mins to figure out where we are going to navigate to and are we swimming or pulling a tube first etc.

I start the boat back up and take of and still seems like it somewhat okay but maybe a little less power than usual. Then from then on it got worse and worse of lossing power. The idle started feeling odd but then it would clear up.

We would take off and some times get on plane and other times it would just stay at 6000-6200 rpm and go 12-14 mph. it would then hook up and go 30+ while it would be stuck at 12-14mph it would just randomly snap out of it THEN it would decelearate back down again. One time it was stuck at 12-14 and then 5 mins of that speed it just took of and ran like it should for about 2-3 mins and then boom right back to the slow unhappy boat. The boat had the same crew in it of kids and adults we had last year at this same lake when we had no issues flying down the lake previous year.

So i'm trying to figure out if i have bad fuel pump. Bad gas. I did determine that my Wear ring looks to be .500mm+ on one side and just under .500mm on the other side. Shaft seems tight prop looks perfect. Boat has about 150 hours on it. So i'm sure i may have some cavitation but for it just go and slow down and go and slow down seems weird to me and if it was caviation shouldn't i be able to still turn 7200+ rpm like I always have even if it was the Wear ring?

No warning lights have come up etc. The way it acted felt way to consistent for bad gas to be the issue but who knows. Any help would really be appreciated.

 

[Dmitry]

I have similar experience with my Yamha 212x 2016. I'm trying to figure out what can be from. I didn't add any ethonal in the tank before i put it away for winter.

 

[dusman2000]

After Posting I found another person that was having a very very similar issue. And this really feels like what mine could be. HIs was a Fuel Injector which makes a lot of sense. Its a long Thread but read to the very bottom. I appreciate any Thoughts on this. Link posted below

Thanks

https://jetboaters.net/threads/sudden-loss-of-power-rpm.39099/

 

[granitetech]

It might be the spark plugs. Mine was sputtering occasionally and then it wouldn't get above 6000 rpm. Changed the plugs and it is running great now

 

[dusman2000]

I've got 4 NGK LFR6A on my table right now about to put in and see. I have not replaced them since I got the boat but the previous owner had often before i got it. Are these motors known for needing new plugs each year??

 

[Dmitry]

I've got 4 NGK LFR6A on my table right now about to put in and see. I have not replaced them since I got the boat but the previous owner had often before i got it. Are these motors known for needing new plugs each year??

Yamaha recommends you change your spark plugs annualy or after every 100 hours of operation.

 

[Murf'n'surf]

You've described bad spark plug symptoms here. Change them and your issue will go away.

 

[dusman2000]

You've described bad spark plug symptoms here. Change them and your issue will go away.

You where right. Replaced the Spark Plugs (LFR6A) ran the boat tonight. Was able to turn 7600rpm and get up to 42.5mph with a little chop on the water and a 8-10mph wind! I ran about 1/3 of a tank of gas stopping and starting and idle to take off multiple times and it ran perfect.

Thank you everyone for your Reponses!

 

[HangOutdoors]

I change my oil and spark plugs every year and call it good.

 

[Thermobrett]

I follow Yamahas recommended service plan in the owner manual. As I only have 52hrs on my boat I still do the oil change and plugs at the beginning of the season as a piece of mind. These engines are high RPM and I’m sure burn hot so a little money upfront can prevent simple problems down “stream”. Since I have a supercharger on mine, I always run premium fuel as recommended. I like to believe Yamaha did their research during the R&D process and that’s why they tell us to use certain products on our engines.

 

[JBinAZ]

Similar issues as above... first time out on the water this year and my top RPM is 5500 pushing 10mph at WOT. I use good fuel and always add stabilizer. I don't believe it's a fuel issue as the boat fires up fine, it just won't run above 10mph. Could this be as simple as spark plugs? I haven't changed them in a few years. Any other issues I should troubleshoot?

 

[Thermobrett]

Similar issues as above... first time out on the water this year and my top RPM is 5500 pushing 10mph at WOT. I use good fuel and always add stabilizer. I don't believe it's a fuel issue as the boat fires up fine, it just won't run above 10mph. Could this be as simple as spark plugs? I haven't changed them in a few years. Any other issues I should troubleshoot?

Are you sure the bucket is fully open? What’s you usually WOT RPM?

 

[JBehrens]

Similar issues as above... first time out on the water this year and my top RPM is 5500 pushing 10mph at WOT. I use good fuel and always add stabilizer. I don't believe it's a fuel issue as the boat fires up fine, it just won't run above 10mph. Could this be as simple as spark plugs? I haven't changed them in a few years. Any other issues I should troubleshoot?

It could be spark plugs, that is the most common. For the last year I had been chasing a similar issue of surging power and turns out it was an ignition coil pack going bad. If it's a random surge I would think the issue is more electrical, fuel issues would be more consistent.

 

[JetPowered]

Good catch. Had a similar issue on my port engine, put boat on lift but still in water and ran some midrange throttle, un clipped coil pack one by one listening for change in sound and rpm, found no change in cylinder 1, swapped to different spark plug, no change, swap coil pack with starboard engine known good, runs like a dream. Will be ordering a spare coil pack or two.

To OPs question, there are some products that can be added to bind to water in tank if you think you have contaminated fuel. I briefly thought this might be my problem but one engine kept running fine. Go thru the ignition system first.

 

[JBinAZ]

So the culprit was spark plugs. Changed those out and all is back to normal. So this is the 12th season for this boat - an oil change each year, a new marine battery every 3rd year (it's hot in AZ, batteries die young) and now a third set of spark plugs. But that is all that this boat has ever needed. These Yamahas are bulletproof!

 

[dusman2000]

Okay I wanted to update this post in hopes it will help someone else. First thing if you buy the Yamaha Diagnostic kit on Amazon or ebay or wherever and you have a 2013 SX190 or newer model yamaha boat you have to unplug the Gauge wires in order for the diag plug to work. Once I did that the Diagnostics app started working. My problem turned out to be Fuel Injector 1. I took them all out and bought a Fuel Injector Pulser and they all worked as they should. HOWEVER once i put them back in and ran the diag to fire each injector the first injector tapped once. then tapped non on the second try. On the third try after moving the cables around to see if it was getting power it tapped 3 times of the 10 times its suppose to. After further messing with it turned out to be the connector/wire going into the connector. So the issue this whole time wasn't the spark plugs like first thought the only reason that seem to originally fix the issue was moving the wires around to put in the spark plugs and it happen to make the injector wire make contact again. After pulling on the plug a little bit the Connector Came completely apart from the wire. I'm guessing it was tight and the vibration of the motor had worn the wires in two over the years. I took a picture of the connector with the Amazon camera seach feature and found a new connector. I later learned its also the same connector as a 2007 Nissan Pathfinder. Anyways soldered in the connector and my boat is back to running top notch! I wanted to pass all this knowledge along for anyone else that might have issues with Diag Software or injectors!

Hope this helps!

Dustin