why are the Yamaha jet engines so loud ???

[Scottintexas]

I have a MR1 boat and love it but like everyone else's boat they SCREAM when you have boat at speed,

a few weeks ago my daughter and I took a fishing trip and had a boat with two yamaha 250's on the back,

we ran about 7 miles at WOT, I sat at the back right next to the engines and weren't bothered by them at all, I could even talk to the driver,

Just checking the 250's have 4.2L displacement but are roughly the same size as our engines,

seeing the new boats come out I wonder why yamaha hasn't addressed this more as it seems like one the main complaints we here about,

How come the outboards can run so quiet and our jets can't ??

 

[lazergeek]

Jetboats run at 8,000 - 10,000 RPM, Outboards redline at 6,000ish. The Jetpump also creates noise with the water forced through it.

 

[biffdotorg]

Lazergeek beat me to it. I would say with the outboard specifically, it hits 250hp at 5500rpm. That's half the rpm we are running.

The biggest reason the boats use the waverunner engine is that laydown format. The shape of the engine and size is ideal to maintain that low stepover that the Yamaha boats have. This trademark cannot be compromised. And I think most of us would agree it's one of the biggest reasons we own these boats.

Because if a 200hp+ pontoon came with a lowering swim platform, and no outboard in the way, I would be going into debt today.

 

[@JC!]

Jetboats run at 8,000 - 10,000 RPM, Outboards redline at 6,000ish. The Jetpump also creates noise with the water forced through it.

The SVHO redlines around 7800 rpm, the HO tops out around 7650-7700 and, if IIRC, the TR-1 only goes to 8000 as well. Cruising is usually done around 5k so while likely a bit higher than an outboard it's not dramatically so. I believe most of the noise can be attributed to the large open engine compartment that doesn't have a lot of insulation though if you've ever heard a SHO/SVHO ski with a performance waterbox and through hull exhaust you'll think the boats are like sitting in a library.

Because if a 200hp+ pontoon came with a lowering swim platform, and no outboard in the way, I would be going into debt today.

You can go buy a SWITCH! ?

 

[biffdotorg]

The SVHO redlines around 7800 rpm, the HO tops out around 7650-7700 and, if IIRC, the TR-1 only goes to 8000 as well. Cruising is usually done around 5k so while likely a bit higher than an outboard it's not dramatically so. I believe most of the noise can be attributed to the large open engine compartment that doesn't have a lot of insulation though if you've ever heard a SHO/SVHO ski with a performance waterbox and through hull exhaust you'll think the boats are like sitting in a library.



You can go buy a SWITCH! ?

There is a reason their target market calls the Switch expensive, and those that buy comfortable and well appointed brands call it a ghetto POS boat. Switch is the spark of the pontoon world. No plastic boats in my fleet. And still no swim platform on it either. Not saying they won't make a "modular" swim platform in the near future.

 

[FSH 210 Sport]

The SVHO redlines around 7800 rpm, the HO tops out around 7650-7700 and, if IIRC, the TR-1 only goes to 8000 as well. Cruising is usually done around 5k so while likely a bit higher than an outboard it's not dramatically so. I believe most of the noise can be attributed to the large open engine compartment that doesn't have a lot of insulation though if you've ever heard a SHO/SVHO ski with a performance waterbox and through hull exhaust you'll think the boats are like sitting in a library.



You can go buy a SWITCH! ?

Your typical outboard is running at 3500-4000 rpms at best cruise, our jet boats cruise at 6000 to be on plane. The MR-1 engines redlined at 10,000 rpms.

In my R&D on high altitude impellers I can tell you that the impellers have a lot to do with the amount of noise at cruise, with the Skat Traks the perceived noise was half of what it was with the OEM or Solas impellers.

 

[lazergeek]

Lets be honest, does anyone really cruise at only 6,000 RPMs? I mean I did for my fist year trying to get most MPG but now its F it, full throttle everywhere... if conditions permit, MPG difference is minimal

 

[Adrian @ JB Solutions]

Lets be honest, does anyone really cruise at only 6,000 RPMs? I mean I did for my fist year trying to get most MPG but now its F it, full throttle everywhere... if conditions permit, MPG difference is minimal

6k is about all I cruise at.... but we have a ton of traffic and water is never smooth. If it's a nice glassy day I am WOT but that is rare.

 

[bubbasuwannee]

I'm cruising 6k ish as well until I wanna hammer down. Considering some efforts to try and quiet it down some, but those aren't on top of my list.

 

[Beachbummer]

I also this summer got to ride in a 30ft with twin suzuki 300 and it was incredibly quiet. The new outboards are much quieter than the old ones from 20th century.

I was envious of the noise level for sure, BUT each engine cost more than my whole boat, so it's a compromise I can live with. The rear seats are also great vs. Outboard so a lot to consider, but 10k on the mr1 vs 4500 rpm is a big difference.

 

[2kwik4u]

Lazergeek beat me to it. I would say with the outboard specifically, it hits 250hp at 5500rpm. That's half the rpm we are running.

The biggest reason the boats use the waverunner engine is that laydown format. The shape of the engine and size is ideal to maintain that low stepover that the Yamaha boats have. This trademark cannot be compromised. And I think most of us would agree it's one of the biggest reasons we own these boats.

Because if a 200hp+ pontoon came with a lowering swim platform, and no outboard in the way, I would be going into debt today.

It's coming.

Manitou is close. Still a prop, but hidden under the swim deck

Indmar made one, but nobody is selling it yet

 

[Babin Farms]

Huh??? Did someone say something???

I’ve got a herd enough time hearing anyways so the only thing I hear is different pitched ringing.

 

[satovod]

 

[jacoviii]

MR1 motors also ,I believe run through a gear set before the drive shaft.

 

[Beachbummer]

Yes 10,000rpm, but that's not the impeller speed.

 

[jacoviii]

Yes 10,000rpm, but that's not the impeller speed.

Yes but 10k into a gear reduction unit is a real screamer.

 

[biffdotorg]

It's coming.

Manitou is close. Still a prop, but hidden under the swim deck

Indmar made one, but nobody is selling it yet

That submerged outboard from BRP, and also the other one that we talked about with the Ecoboost powered Jet drive. Those both have my attention.

The ecoboost jet drive primarily due to the shallow channel we have. But noise will be the deciding factor more than likely. An ecoboost can make good power at lower RPM's, so it may be the best of both worlds. Jet drive and lower noise.

 

[jocolo21]

It's a jet engine DUH ?

 

[212s]

I have a MR1 boat and love it but like everyone else's boat they SCREAM when you have boat at speed,

Ever owned an I/O with direct exhaust? Much louder than our jetboats - think "poker run" boats. Been there, done that.

How come the outboards can run so quiet and our jets can't ??

1- outboards have underwater exhaust
2 - outboards don't rev as high
3 - outboards don't have jetpumps with massive reverberation directly attached to the hull

Number 3 is the big one - about 50% of the "engine" noise is actually from the jetpump housings. I/O drives have the prop outside the hull so that helps a bit, but my older I/O boats were still quite loud with engine noise. Unless you spend big bucks and get into larger bowriders from Monterey or Cobalt, etc, you're going to hear inboard engine noise.

Also remember that the water noise from the spray is about 25% of the noise. I notice cruising with the bimini closed is much quieter as the water spray noise is not reflected off the bimini into the the cockpit.

My solution? Turn up the tunes and punch it!
?

 

[gthh]

No one mention ear muffs???