Sx195 power loss

[Jarheadland]

I’m new to boating and appreciate the forum. We bought a 2020 SX195 about 10 weeks ago. For the last 2-3 weeks it has had a significant power loss at top end. My recent max rpm is ~5800. I have 39 hours on it. I changed the spark plugs and only gained about 200-300 rpms. Still well below what it should be. Checked all clean outs for blockage. When I go full throttle it acts like a governor and pulls back down. Any ideas?

 

[Gunner]

Overfilled oil saturating air filter, obstruction in jet pump/impeller or bad spark plug?

 

[anmut]

It's still under warranty, get it to your dealership!

 

[Canuckjetboater]

I’m new to boating and appreciate the forum. We bought a 2020 SX195 about 10 weeks ago. For the last 2-3 weeks it has had a significant power loss at top end. My recent max rpm is ~5800. I have 39 hours on it. I changed the spark plugs and only gained about 200-300 rpms. Still well below what it should be. Checked all clean outs for blockage. When I go full throttle it acts like a governor and pulls back down. Any ideas?

@Jarheadland ....do you have full range of your throttle....and is it activating at the engine? If not there are only two things I can think of that restrict RPM - choked airflow or choked/bad fuel. As has been suggested check oil level and better yet have the dealership water test it.

 

[Jarheadland]

I do have full range or throttle. I was able to confirm while on trailer. However, the throttle lever between 85% full to 100% full does not provide any additional power thrust. Seems that 85% throttle is the new full throttle.

 

[ScottS]

Where are you boating? (Elevation). What is the temperature difference from when you first got the boat and when you experience the worst loss of performance? I lose around 300-500 RPM from cool morning temps to daytime highs.

Edit: Also, have you had your 10-hour service?

 

[BlueJet20]

This has been the biggest cluster. We ended up calling Yamaha and the gentleman we spoke to knew exactly what the problem was. They couldn’t tell us, but called the dealer and told them what to look for. Turns out the foam or sound cancelling insulation around the air filter box is causing an airflow issue. You have to remove this foam. We haven’t tested boat yet, but a guy with same boat posted the same thing in another board I’m on. Fingers crossed.

 

[Jarheadland]

This has been the biggest cluster. We ended up calling Yamaha and the gentleman we spoke to knew exactly what the problem was. They couldn’t tell us, but called the dealer and told them what to look for. Turns out the foam or sound cancelling insulation around the air filter box is causing an airflow issue. You have to remove this foam. We haven’t tested boat yet, but a guy with same boat posted the same thing in another board I’m on. Fingers crossed.

Wow. I hope this works. What a painful journey you’ve been on. We have resigned to just deal with it until the end of the season. But if it works that would be great.

 

[Jarheadland]

Wow. I hope this works. What a painful journey you’ve been on. We have resigned to just deal with it until the end of the season. But if it works that would be great.

@BlueJet20 I took a look at mine to understand what you're talking about. I have a little slice of foam along the side of my air box but can't imagine how that would influence. Hopefully you have success. Send pics if you can.

 

[marcham]

Does it still run smooth? if so My guess is a loose hose from the supercharger....

 

[BlueJet20]

@BlueJet20 I took a look at mine to understand what you're talking about. I have a little slice of foam along the side of my air box but can't imagine how that would influence. Hopefully you have success. Send pics if you can.

Took the boat out yesterday. Sure enough, problem solved. Back to full throttle and full RPM. I’ll try to post a pic later. But, yes, the foam is what they had to cut off. I never would’ve figured that one out. The Yamaha rep told us our issue was an air issue, so it makes sense as the foam is blocking the air intake.

 

[Jarheadland]

Took the boat out yesterday. Sure enough, problem solved. Back to full throttle and full RPM. I’ll try to post a pic later. But, yes, the foam is what they had to cut off. I never would’ve figured that one out. The Yamaha rep told us our issue was an air issue, so it makes sense as the foam is blocking the air intake.

Great. I’m glad that works. I’ll try the same as soon as the storms clear and we drop the boat.

 

[sebmcadet]

Please send pics! -- Having a similar issue with AR192. Though my power loss has been very gradual over the last weekend only. Still investigating.

 

[marcham]

Any update?

 

[Chris D]

Yes pictures please.

 

[BlueJet20]

Please send pics! -- Having a similar issue with AR192. Though my power loss has been very gradual over the last weekend only. Still investigating.

Blue arrow points to the air intake. Red arrow points to the foam that hangs over the air intake. They cut the foam away. Hope this makes sense.

 

[BlueJet20]

Yes pictures please.

Blue arrow points to the air intake. Red arrow points to the foam that hangs over the air intake. They cut the foam away. Hope this makes sense.

 

[sebmcadet]

Blue arrow points to the air intake. Red arrow points to the foam that hangs over the air intake. They cut the foam away. Hope this makes sense.

Thanks @BlueJet20 for sharing!
This does make sense.
I see the placement of the air filter is slightly different than in my 2014 AR192.
It's further back and to the side of the engine.

I removed the Yamaha air filter box and looked at the filter as I was troubleshooting where my power loss was coming from.
In the process, I thought I'd change the filter, but these are super expansive!
So I followed other 19" owners and changed the entire thing for a large K&N filter. (See attachment)
Lake tested it today and it works fine.

However, I still can't get over 6900 rpm!!
ADVICES WELCOMED!

 

[ScottS]

@sebmcadet If you are bored, read through my account below in working to get my boat to perform better.

https://jetboaters.net/threads/2017-yamaha-ar195-working-through-issues-at-elevation-addressing-performance.28099/

TLDR: Make sure you have a prop tuned to your elevation. Riva Spacer/Ribbon delete seems like a good idea. L13 Cone can help with the low end hole shot. The temperature of Air and Water increasing as the season progresses results in lower peak RPM's - you will notice higher RPM's if you get out in the morning when the air is cooler. Make sure your intake and tunnel are sealed with silicone. Properly gap your plugs.

 

[sebmcadet]

@ScottS Thanks for your message!
Planning on changing my plugs this weekend. I have the round plug gapper. So even though it's not super accurate I'll make sure all four plugs have about the same gap.
Where would you apply silicone in the intake? I've just changed my air filter. What do you call tunnel?